diff --git a/features/bootstrap/DoctrineContext.php b/features/bootstrap/DoctrineContext.php
index c6c4ba87e9e..319c717e9ce 100644
--- a/features/bootstrap/DoctrineContext.php
+++ b/features/bootstrap/DoctrineContext.php
@@ -15,6 +15,7 @@
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\AbsoluteUrlRelationDummy as AbsoluteUrlRelationDummyDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\Address as AddressDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\Answer as AnswerDocument;
+use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\Book as BookDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\CompositeItem as CompositeItemDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\CompositeLabel as CompositeLabelDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\CompositePrimitiveItem as CompositePrimitiveItemDocument;
@@ -26,6 +27,7 @@
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\ConvertedRelated as ConvertedRelatedDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\ConvertedString as ConvertedStringDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\Customer as CustomerDocument;
+use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\CustomMultipleIdentifierDummy as CustomMultipleIdentifierDummyDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\Dummy as DummyDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\DummyAggregateOffer as DummyAggregateOfferDocument;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Document\DummyCar as DummyCarDocument;
@@ -78,6 +80,7 @@
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\AbsoluteUrlRelationDummy;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Address;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Answer;
+use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Book;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\CompositeItem;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\CompositeLabel;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\CompositePrimitiveItem;
@@ -89,6 +92,7 @@
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\ConvertedRelated;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\ConvertedString;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Customer;
+use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\CustomMultipleIdentifierDummy;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\DummyAggregateOffer;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\DummyCar;
@@ -1605,6 +1609,32 @@ public function thereIsAnInitializeInput(int $id)
         $this->manager->flush();
     }
 
+    /**
+     * @Given there is a book
+     */
+    public function thereIsABook()
+    {
+        $book = $this->buildBook();
+        $book->name = '1984';
+        $book->isbn = '9780451524935';
+        $this->manager->persist($book);
+        $this->manager->flush();
+    }
+
+    /**
+     * @Given there is a custom multiple identifier dummy
+     */
+    public function thereIsACustomMultipleIdentifierDummy()
+    {
+        $dummy = $this->buildCustomMultipleIdentifierDummy();
+        $dummy->setName('Orwell');
+        $dummy->setFirstId(1);
+        $dummy->setSecondId(2);
+
+        $this->manager->persist($dummy);
+        $this->manager->flush();
+    }
+
     private function isOrm(): bool
     {
         return null !== $this->schemaTool;
@@ -2030,4 +2060,20 @@ private function buildInitializeInput()
     {
         return $this->isOrm() ? new InitializeInput() : new InitializeInputDocument();
     }
+
+    /**
+     * @return BookDocument | Book
+     */
+    private function buildBook()
+    {
+        return $this->isOrm() ? new Book() : new BookDocument();
+    }
+
+    /**
+     * @return CustomMultipleIdentifierDummy | CustomMultipleIdentifierDummyDocument
+     */
+    private function buildCustomMultipleIdentifierDummy()
+    {
+        return $this->isOrm() ? new CustomMultipleIdentifierDummy() : new CustomMultipleIdentifierDummyDocument();
+    }
 }
diff --git a/features/json/relation.feature b/features/json/relation.feature
index 7c39dc75f71..57e7e41cbf1 100644
--- a/features/json/relation.feature
+++ b/features/json/relation.feature
@@ -156,7 +156,7 @@ Feature: JSON relations support
     And I send a "POST" request to "/related_dummies" with body:
     """
     {
-      "thirdLevel": "1"
+      "thirdLevel": "/third_levels/1"
     }
     """
     Then the response status code should be 201
@@ -184,16 +184,16 @@ Feature: JSON relations support
     }
     """
 
-  Scenario: Passing a (valid) plain identifier on a relation
+  Scenario: Create a Dummy with relations to RelatedDummy
     When I add "Content-Type" header equal to "application/json"
     And I send a "POST" request to "/dummies" with body:
     """
     {
-      "relatedDummy": "1",
+      "relatedDummy": "/related_dummies/1",
       "relatedDummies": [
-        "1"
+        "/related_dummies/1"
       ],
-      "name": "Dummy with plain relations"
+      "name": "Dummy with relations"
     }
     """
     Then the response status code should be 201
@@ -221,7 +221,7 @@ Feature: JSON relations support
       "relatedOwnedDummy": null,
       "relatedOwningDummy": null,
       "id": 1,
-      "name": "Dummy with plain relations",
+      "name": "Dummy with relations",
       "alias": null,
       "foo": null
     }
diff --git a/features/main/custom_identifier.feature b/features/main/custom_identifier.feature
index ba37934d76b..6c078bcc684 100644
--- a/features/main/custom_identifier.feature
+++ b/features/main/custom_identifier.feature
@@ -101,3 +101,21 @@ Feature: Using custom identifier on resource
     When I send a "DELETE" request to "/custom_identifier_dummies/1"
     Then the response status code should be 204
     And the response should be empty
+
+  @createSchema
+  Scenario: Get a resource
+    Given there is a custom multiple identifier dummy
+    When I send a "GET" request to "/custom_multiple_identifier_dummies/1/2"
+    Then the response status code should be 200
+    And the response should be in JSON
+    And the JSON should be equal to:
+    """
+    {
+      "@context": "/contexts/CustomMultipleIdentifierDummy",
+      "@id": "/custom_multiple_identifier_dummies/1/2",
+      "@type": "CustomMultipleIdentifierDummy",
+      "firstId": 1,
+      "secondId": 2,
+      "name": "Orwell"
+    }
+    """
diff --git a/features/main/operation.feature b/features/main/operation.feature
index 8c70d1c2b99..c5f885a33f3 100644
--- a/features/main/operation.feature
+++ b/features/main/operation.feature
@@ -63,3 +63,23 @@ Feature: Operation support
   Scenario: Get a 404 response for the disabled item operation
     When I send a "GET" request to "/disable_item_operations/1"
     Then the response status code should be 404
+
+  @createSchema
+  Scenario: Get a book by its ISBN
+    Given there is a book
+    When I send a "GET" request to "books/by_isbn/9780451524935"
+    Then the response status code should be 200
+    And the response should be in JSON
+    And the header "Content-Type" should be equal to "application/ld+json; charset=utf-8"
+    And the JSON should be equal to:
+    """
+    {
+        "@context": "/contexts/Book",
+        "@id": "/books/1",
+        "@type": "Book",
+        "name": "1984",
+        "isbn": "9780451524935",
+        "id": 1
+    }
+    """
+
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
index 4cd9ea3abb1..b15cbb85bd0 100644
--- a/phpstan.neon.dist
+++ b/phpstan.neon.dist
@@ -138,3 +138,9 @@ parameters:
 			paths:
 				- src/Bridge/Elasticsearch/DataProvider/Filter/OrderFilter.php
 				- src/Bridge/Elasticsearch/DataProvider/Filter/AbstractSearchFilter.php
+
+		-
+			message: '#Unreachable statement - code above always terminates.#'
+			paths:
+				- tests/Serializer/AbstractItemNormalizerTest.php 
+				- tests/Bridge/Doctrine/MongoDbOdm/ItemDataProviderTest.php
diff --git a/phpunit_mongodb.xml b/phpunit_mongodb.xml
index 051f8f9e583..cb677f9e30a 100644
--- a/phpunit_mongodb.xml
+++ b/phpunit_mongodb.xml
@@ -10,7 +10,10 @@
     <php>
         <ini name="error_reporting" value="-1" />
         <ini name="memory_limit" value="-1" />
-        <env name="SYMFONY_DEPRECATIONS_HELPER" value="max[self]=0" />
+        <server name="SYMFONY_DEPRECATIONS_HELPER" value="max[self]=0" />
+        <!-- This is necessary for GitHub Actions to work properly -->
+        <server name="SYMFONY_PHPUNIT_DIR" value="vendor/bin/.phpunit" />
+        <server name="SYMFONY_PHPUNIT_REMOVE" value="symfony/yaml" />
         <server name="KERNEL_DIR" value="tests/Fixtures/app/" />
         <server name="KERNEL_CLASS" value="AppKernel" />
         <server name="APP_ENV" value="mongodb" />
diff --git a/src/Annotation/ApiResource.php b/src/Annotation/ApiResource.php
index 831fd76f0cd..b7102812d7b 100644
--- a/src/Annotation/ApiResource.php
+++ b/src/Annotation/ApiResource.php
@@ -28,6 +28,7 @@
  *     @Attribute("attributes", type="array"),
  *     @Attribute("cacheHeaders", type="array"),
  *     @Attribute("collectionOperations", type="array"),
+ *     @Attribute("compositeIdentifier", type="bool"),
  *     @Attribute("denormalizationContext", type="array"),
  *     @Attribute("deprecationReason", type="string"),
  *     @Attribute("description", type="string"),
@@ -89,6 +90,7 @@ final class ApiResource
         'securityPostDenormalizeMessage',
         'cacheHeaders',
         'collectionOperations',
+        'compositeIdentifier',
         'denormalizationContext',
         'deprecationReason',
         'description',
@@ -452,6 +454,13 @@ final class ApiResource
      */
     private $urlGenerationStrategy;
 
+    /**
+     * @see https://github.com/Haehnchen/idea-php-annotation-plugin/issues/112
+     *
+     * @var bool
+     */
+    private $compositeIdentifier;
+
     /**
      * @throws InvalidArgumentException
      */
diff --git a/src/Bridge/Doctrine/MongoDbOdm/ItemDataProvider.php b/src/Bridge/Doctrine/MongoDbOdm/ItemDataProvider.php
index 12db2dda163..d58c0d919a5 100644
--- a/src/Bridge/Doctrine/MongoDbOdm/ItemDataProvider.php
+++ b/src/Bridge/Doctrine/MongoDbOdm/ItemDataProvider.php
@@ -16,10 +16,9 @@
 use ApiPlatform\Core\Bridge\Doctrine\Common\Util\IdentifierManagerTrait;
 use ApiPlatform\Core\Bridge\Doctrine\MongoDbOdm\Extension\AggregationItemExtensionInterface;
 use ApiPlatform\Core\Bridge\Doctrine\MongoDbOdm\Extension\AggregationResultItemExtensionInterface;
-use ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface;
+use ApiPlatform\Core\DataProvider\ItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\RestrictedDataProviderInterface;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
@@ -34,7 +33,7 @@
  *
  * @author Alan Poulain <contact@alanpoulain.eu>
  */
-final class ItemDataProvider implements DenormalizedIdentifiersAwareItemDataProviderInterface, RestrictedDataProviderInterface
+final class ItemDataProvider implements ItemDataProviderInterface, RestrictedDataProviderInterface
 {
     use IdentifierManagerTrait;
 
@@ -64,19 +63,13 @@ public function supports(string $resourceClass, string $operationName = null, ar
      *
      * @throws RuntimeException
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, ?string $operationName = null, array $context = [])
     {
         /** @var DocumentManager $manager */
         $manager = $this->managerRegistry->getManagerForClass($resourceClass);
 
-        if (!\is_array($id) && !($context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] ?? false)) {
-            $id = $this->normalizeIdentifiers($id, $manager, $resourceClass);
-        }
-
-        $id = (array) $id;
-
         if (!($context['fetch_data'] ?? true)) {
-            return $manager->getReference($resourceClass, reset($id));
+            return $manager->getReference($resourceClass, reset($identifiers));
         }
 
         $repository = $manager->getRepository($resourceClass);
@@ -86,12 +79,12 @@ public function getItem(string $resourceClass, $id, string $operationName = null
 
         $aggregationBuilder = $repository->createAggregationBuilder();
 
-        foreach ($id as $propertyName => $value) {
+        foreach ($identifiers as $propertyName => $value) {
             $aggregationBuilder->match()->field($propertyName)->equals($value);
         }
 
         foreach ($this->itemExtensions as $extension) {
-            $extension->applyToItem($aggregationBuilder, $resourceClass, $id, $operationName, $context);
+            $extension->applyToItem($aggregationBuilder, $resourceClass, $identifiers, $operationName, $context);
 
             if ($extension instanceof AggregationResultItemExtensionInterface && $extension->supportsResult($resourceClass, $operationName, $context)) {
                 return $extension->getResult($aggregationBuilder, $resourceClass, $operationName, $context);
diff --git a/src/Bridge/Doctrine/MongoDbOdm/SubresourceDataProvider.php b/src/Bridge/Doctrine/MongoDbOdm/SubresourceDataProvider.php
index beceaf0a22d..16a2e05b06c 100644
--- a/src/Bridge/Doctrine/MongoDbOdm/SubresourceDataProvider.php
+++ b/src/Bridge/Doctrine/MongoDbOdm/SubresourceDataProvider.php
@@ -21,7 +21,6 @@
 use ApiPlatform\Core\DataProvider\SubresourceDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
@@ -136,24 +135,14 @@ private function buildAggregation(array $identifiers, array $context, array $exe
         }
 
         $aggregation = $manager->createAggregationBuilder($identifierResourceClass);
-        $normalizedIdentifiers = [];
-
-        if (isset($identifiers[$identifier])) {
-            // if it's an array it's already normalized, the IdentifierManagerTrait is deprecated
-            if ($context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] ?? false) {
-                $normalizedIdentifiers = $identifiers[$identifier];
-            } else {
-                $normalizedIdentifiers = $this->normalizeIdentifiers($identifiers[$identifier], $manager, $identifierResourceClass);
-            }
-        }
 
         if ($classMetadata->hasAssociation($previousAssociationProperty)) {
             $aggregation->lookup($previousAssociationProperty)->alias($previousAssociationProperty);
-            foreach ($normalizedIdentifiers as $key => $value) {
+            foreach (\is_array($identifiers[$identifier]) ? $identifiers[$identifier] : $identifiers as $key => $value) {
                 $aggregation->match()->field($key)->equals($value);
             }
         } elseif ($classMetadata->isIdentifier($previousAssociationProperty)) {
-            foreach ($normalizedIdentifiers as $key => $value) {
+            foreach (\is_array($identifiers[$identifier]) ? $identifiers[$identifier] : $identifiers as $key => $value) {
                 $aggregation->match()->field($key)->equals($value);
             }
 
diff --git a/src/Bridge/Doctrine/Orm/ItemDataProvider.php b/src/Bridge/Doctrine/Orm/ItemDataProvider.php
index 9535b162427..3c826a10ed3 100644
--- a/src/Bridge/Doctrine/Orm/ItemDataProvider.php
+++ b/src/Bridge/Doctrine/Orm/ItemDataProvider.php
@@ -13,20 +13,16 @@
 
 namespace ApiPlatform\Core\Bridge\Doctrine\Orm;
 
-use ApiPlatform\Core\Bridge\Doctrine\Common\Util\IdentifierManagerTrait;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryItemExtensionInterface;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryResultItemExtensionInterface;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Util\QueryNameGenerator;
-use ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface;
+use ApiPlatform\Core\DataProvider\ItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\RestrictedDataProviderInterface;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
+use Doctrine\Common\Persistence\ManagerRegistry;
+use Doctrine\Common\Persistence\Mapping\ClassMetadata;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\QueryBuilder;
-use Doctrine\Persistence\ManagerRegistry;
-use Doctrine\Persistence\Mapping\ClassMetadata;
 
 /**
  * Item data provider for the Doctrine ORM.
@@ -35,21 +31,17 @@
  * @author Samuel ROZE <samuel.roze@gmail.com>
  * @final
  */
-class ItemDataProvider implements DenormalizedIdentifiersAwareItemDataProviderInterface, RestrictedDataProviderInterface
+class ItemDataProvider implements ItemDataProviderInterface, RestrictedDataProviderInterface
 {
-    use IdentifierManagerTrait;
-
     private $managerRegistry;
     private $itemExtensions;
 
     /**
      * @param QueryItemExtensionInterface[] $itemExtensions
      */
-    public function __construct(ManagerRegistry $managerRegistry, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, iterable $itemExtensions = [])
+    public function __construct(ManagerRegistry $managerRegistry, iterable $itemExtensions = [])
     {
         $this->managerRegistry = $managerRegistry;
-        $this->propertyNameCollectionFactory = $propertyNameCollectionFactory;
-        $this->propertyMetadataFactory = $propertyMetadataFactory;
         $this->itemExtensions = $itemExtensions;
     }
 
@@ -65,19 +57,11 @@ public function supports(string $resourceClass, string $operationName = null, ar
      *
      * @throws RuntimeException
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         /** @var EntityManagerInterface $manager */
         $manager = $this->managerRegistry->getManagerForClass($resourceClass);
 
-        if ((\is_int($id) || \is_string($id)) && !($context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] ?? false)) {
-            $id = $this->normalizeIdentifiers($id, $manager, $resourceClass);
-        }
-        if (!\is_array($id)) {
-            throw new \InvalidArgumentException(sprintf('$id must be array when "%s" key is set to true in the $context', IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER));
-        }
-        $identifiers = $id;
-
         $fetchData = $context['fetch_data'] ?? true;
         if (!$fetchData) {
             return $manager->getReference($resourceClass, $identifiers);
@@ -119,7 +103,6 @@ private function addWhereForIdentifiers(array $identifiers, QueryBuilder $queryB
             );
 
             $queryBuilder->andWhere($expression);
-
             $queryBuilder->setParameter($placeholder, $value, $classMetadata->getTypeOfField($identifier));
         }
     }
diff --git a/src/Bridge/Doctrine/Orm/SubresourceDataProvider.php b/src/Bridge/Doctrine/Orm/SubresourceDataProvider.php
index 9438a708fde..3238ee11db2 100644
--- a/src/Bridge/Doctrine/Orm/SubresourceDataProvider.php
+++ b/src/Bridge/Doctrine/Orm/SubresourceDataProvider.php
@@ -13,7 +13,6 @@
 
 namespace ApiPlatform\Core\Bridge\Doctrine\Orm;
 
-use ApiPlatform\Core\Bridge\Doctrine\Common\Util\IdentifierManagerTrait;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\FilterEagerLoadingExtension;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryCollectionExtensionInterface;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryItemExtensionInterface;
@@ -23,13 +22,10 @@
 use ApiPlatform\Core\DataProvider\SubresourceDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
+use Doctrine\Common\Persistence\ManagerRegistry;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Mapping\ClassMetadataInfo;
 use Doctrine\ORM\QueryBuilder;
-use Doctrine\Persistence\ManagerRegistry;
 
 /**
  * Subresource data provider for the Doctrine ORM.
@@ -38,8 +34,6 @@
  */
 final class SubresourceDataProvider implements SubresourceDataProviderInterface
 {
-    use IdentifierManagerTrait;
-
     private $managerRegistry;
     private $collectionExtensions;
     private $itemExtensions;
@@ -48,11 +42,9 @@ final class SubresourceDataProvider implements SubresourceDataProviderInterface
      * @param QueryCollectionExtensionInterface[] $collectionExtensions
      * @param QueryItemExtensionInterface[]       $itemExtensions
      */
-    public function __construct(ManagerRegistry $managerRegistry, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, iterable $collectionExtensions = [], iterable $itemExtensions = [])
+    public function __construct(ManagerRegistry $managerRegistry, iterable $collectionExtensions = [], iterable $itemExtensions = [])
     {
         $this->managerRegistry = $managerRegistry;
-        $this->propertyNameCollectionFactory = $propertyNameCollectionFactory;
-        $this->propertyMetadataFactory = $propertyMetadataFactory;
         $this->collectionExtensions = $collectionExtensions;
         $this->itemExtensions = $itemExtensions;
     }
@@ -147,16 +139,6 @@ private function buildQuery(array $identifiers, array $context, QueryNameGenerat
 
         $qb = $manager->createQueryBuilder();
         $alias = $queryNameGenerator->generateJoinAlias($identifier);
-        $normalizedIdentifiers = [];
-
-        if (isset($identifiers[$identifier])) {
-            // if it's an array it's already normalized, the IdentifierManagerTrait is deprecated
-            if ($context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] ?? false) {
-                $normalizedIdentifiers = $identifiers[$identifier];
-            } else {
-                $normalizedIdentifiers = $this->normalizeIdentifiers($identifiers[$identifier], $manager, $identifierResourceClass);
-            }
-        }
 
         if ($classMetadata->hasAssociation($previousAssociationProperty)) {
             $relationType = $classMetadata->getAssociationMapping($previousAssociationProperty)['type'];
@@ -201,7 +183,7 @@ private function buildQuery(array $identifiers, array $context, QueryNameGenerat
         $isLeaf = 1 === $remainingIdentifiers;
 
         // Add where clause for identifiers
-        foreach ($normalizedIdentifiers as $key => $value) {
+        foreach (\is_array($identifiers[$identifier]) ? $identifiers[$identifier] : $identifiers as $key => $value) {
             $placeholder = $queryNameGenerator->generateParameterName($key);
             $topQueryBuilder->setParameter($placeholder, $value, (string) $classMetadata->getTypeOfField($key));
 
diff --git a/src/Bridge/Elasticsearch/DataProvider/ItemDataProvider.php b/src/Bridge/Elasticsearch/DataProvider/ItemDataProvider.php
index 9d3fcb1c75e..6bc92299294 100644
--- a/src/Bridge/Elasticsearch/DataProvider/ItemDataProvider.php
+++ b/src/Bridge/Elasticsearch/DataProvider/ItemDataProvider.php
@@ -83,19 +83,15 @@ public function supports(string $resourceClass, ?string $operationName = null, a
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, ?string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, ?string $operationName = null, array $context = [])
     {
-        if (\is_array($id)) {
-            $id = $id[$this->identifierExtractor->getIdentifierFromResourceClass($resourceClass)];
-        }
-
         $documentMetadata = $this->documentMetadataFactory->create($resourceClass);
 
         try {
             $document = $this->client->get([
                 'index' => $documentMetadata->getIndex(),
                 'type' => $documentMetadata->getType(),
-                'id' => (string) $id,
+                'id' => $identifiers[$this->identifierExtractor->getIdentifierFromResourceClass($resourceClass)],
             ]);
         } catch (Missing404Exception $e) {
             return null;
diff --git a/src/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataProvider.php b/src/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataProvider.php
index 0b95ece153a..6dcfd03ea7e 100644
--- a/src/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataProvider.php
+++ b/src/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataProvider.php
@@ -14,7 +14,6 @@
 namespace ApiPlatform\Core\Bridge\Symfony\Bundle\DataProvider;
 
 use ApiPlatform\Core\DataProvider\ChainItemDataProvider;
-use ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\ItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\RestrictedDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
@@ -45,7 +44,7 @@ public function getContext(): array
         return $this->context;
     }
 
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         $this->context = $context;
         $match = false;
@@ -62,17 +61,7 @@ public function getItem(string $resourceClass, $id, string $operationName = null
                     continue;
                 }
 
-                $identifier = $id;
-                if (!$dataProvider instanceof DenormalizedIdentifiersAwareItemDataProviderInterface && $identifier && \is_array($identifier)) {
-                    if (\count($identifier) > 1) {
-                        @trigger_error(sprintf('Receiving "$id" as non-array in an item data provider is deprecated in 2.3 in favor of implementing "%s".', DenormalizedIdentifiersAwareItemDataProviderInterface::class), E_USER_DEPRECATED);
-                        $identifier = http_build_query($identifier, '', ';');
-                    } else {
-                        $identifier = current($identifier);
-                    }
-                }
-
-                $result = $dataProvider->getItem($resourceClass, $identifier, $operationName, $context);
+                $result = $dataProvider->getItem($resourceClass, $identifiers, $operationName, $context);
                 $this->providersResponse[\get_class($dataProvider)] = $match = true;
             } catch (ResourceClassNotSupportedException $e) {
                 @trigger_error(sprintf('Throwing a "%s" is deprecated in favor of implementing "%s"', \get_class($e), RestrictedDataProviderInterface::class), E_USER_DEPRECATED);
diff --git a/src/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php b/src/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php
index b7bf18a94d1..c1b77f220e4 100644
--- a/src/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php
+++ b/src/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtension.php
@@ -184,7 +184,6 @@ private function registerCommonConfiguration(ContainerBuilder $container, array
         $container->setParameter('api_platform.formats', $formats);
         $container->setParameter('api_platform.patch_formats', $patchFormats);
         $container->setParameter('api_platform.error_formats', $errorFormats);
-        $container->setParameter('api_platform.allow_plain_identifiers', $config['allow_plain_identifiers']);
         $container->setParameter('api_platform.eager_loading.enabled', $this->isConfigEnabled($container, $config['eager_loading']));
         $container->setParameter('api_platform.eager_loading.max_joins', $config['eager_loading']['max_joins']);
         $container->setParameter('api_platform.eager_loading.fetch_partial', $config['eager_loading']['fetch_partial']);
diff --git a/src/Bridge/Symfony/Bundle/DependencyInjection/Configuration.php b/src/Bridge/Symfony/Bundle/DependencyInjection/Configuration.php
index 51ca4471e2b..738f36b5164 100644
--- a/src/Bridge/Symfony/Bundle/DependencyInjection/Configuration.php
+++ b/src/Bridge/Symfony/Bundle/DependencyInjection/Configuration.php
@@ -93,7 +93,6 @@ public function getConfigTreeBuilder()
                 ->end()
                 ->scalarNode('name_converter')->defaultNull()->info('Specify a name converter to use.')->end()
                 ->scalarNode('path_segment_name_generator')->defaultValue('api_platform.path_segment_name_generator.underscore')->info('Specify a path name generator to use.')->end()
-                ->booleanNode('allow_plain_identifiers')->defaultFalse()->info('Allow plain identifiers, for example "id" instead of "@id" when denormalizing a relation.')->end()
                 ->arrayNode('validator')
                     ->addDefaultsIfNotSet()
                     ->children()
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/api.xml b/src/Bridge/Symfony/Bundle/Resources/config/api.xml
index ffa00199f6d..7530e3dc267 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/api.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/api.xml
@@ -43,6 +43,7 @@
             <argument>%api_platform.enable_docs%</argument>
             <argument>%api_platform.graphql.graphiql.enabled%</argument>
             <argument>%api_platform.graphql.graphql_playground.enabled%</argument>
+            <argument type="service" id="api_platform.identifiers_extractor.cached"></argument>
 
             <tag name="routing.loader" />
         </service>
@@ -55,15 +56,12 @@
         </service>
 
         <service id="api_platform.iri_converter" class="ApiPlatform\Core\Bridge\Symfony\Routing\IriConverter" public="false">
-            <argument type="service" id="api_platform.metadata.property.name_collection_factory" />
-            <argument type="service" id="api_platform.metadata.property.metadata_factory" />
             <argument type="service" id="api_platform.item_data_provider" />
             <argument type="service" id="api_platform.route_name_resolver" />
             <argument type="service" id="api_platform.router" />
-            <argument type="service" id="api_platform.property_accessor" />
             <argument type="service" id="api_platform.identifiers_extractor.cached" />
             <argument type="service" id="api_platform.subresource_data_provider" on-invalid="ignore" />
-            <argument type="service" id="api_platform.identifier.converter" on-invalid="ignore" />
+            <argument type="service" id="api_platform.identifier.denormalizer" on-invalid="ignore" />
             <argument type="service" id="api_platform.resource_class_resolver" />
             <argument type="service" id="api_platform.metadata.resource.metadata_factory" />
         </service>
@@ -110,7 +108,6 @@
             <argument type="service" id="api_platform.name_converter" on-invalid="ignore" />
             <argument type="service" id="serializer.mapping.class_metadata_factory" on-invalid="ignore" />
             <argument type="service" id="api_platform.item_data_provider" on-invalid="ignore" />
-            <argument>%api_platform.allow_plain_identifiers%</argument>
             <argument>null</argument>
             <argument type="tagged" tag="api_platform.data_transformer" on-invalid="ignore" />
             <argument type="service" id="api_platform.metadata.resource.metadata_factory" on-invalid="ignore" />
@@ -163,7 +160,7 @@
             <argument type="service" id="api_platform.item_data_provider" />
             <argument type="service" id="api_platform.subresource_data_provider" />
             <argument type="service" id="api_platform.serializer.context_builder" />
-            <argument type="service" id="api_platform.identifier.converter" />
+            <argument type="service" id="api_platform.identifier.denormalizer" />
             <argument type="service" id="api_platform.metadata.resource.metadata_factory" />
 
             <tag name="kernel.event_listener" event="kernel.request" method="onKernelRequest" priority="4" />
@@ -265,8 +262,7 @@
         </service>
         <service id="ApiPlatform\Core\Api\IdentifiersExtractorInterface" alias="api_platform.identifiers_extractor.cached" />
 
-        <service id="api_platform.identifier.converter" class="ApiPlatform\Core\Identifier\IdentifierConverter" public="false">
-            <argument type="service" id="api_platform.identifiers_extractor.cached" />
+        <service id="api_platform.identifier.denormalizer" class="ApiPlatform\Core\Identifier\IdentifierDenormalizer" public="false">
             <argument type="service" id="api_platform.metadata.property.metadata_factory" />
             <argument type="tagged" tag="api_platform.identifier.denormalizer" />
         </service>
@@ -286,6 +282,7 @@
             <argument type="service" id="api_platform.metadata.property.name_collection_factory" />
             <argument type="service" id="api_platform.metadata.property.metadata_factory" />
             <argument type="service" id="api_platform.path_segment_name_generator" />
+            <argument type="service" id="api_platform.identifiers_extractor.cached" />
         </service>
 
         <service id="api_platform.subresource_operation_factory.cached" class="ApiPlatform\Core\Operation\Factory\CachedSubresourceOperationFactory" decorates="api_platform.subresource_operation_factory" decoration-priority="-10" public="false">
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/doctrine_orm.xml b/src/Bridge/Symfony/Bundle/Resources/config/doctrine_orm.xml
index f60b7d564af..25390c8bc76 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/doctrine_orm.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/doctrine_orm.xml
@@ -22,15 +22,11 @@
 
         <service id="api_platform.doctrine.orm.item_data_provider" public="false" abstract="true">
             <argument type="service" id="doctrine" />
-            <argument type="service" id="api_platform.metadata.property.name_collection_factory" />
-            <argument type="service" id="api_platform.metadata.property.metadata_factory" />
             <argument type="tagged" tag="api_platform.doctrine.orm.query_extension.item" />
         </service>
 
         <service id="api_platform.doctrine.orm.subresource_data_provider" public="false" abstract="true">
             <argument type="service" id="doctrine" />
-            <argument type="service" id="api_platform.metadata.property.name_collection_factory" />
-            <argument type="service" id="api_platform.metadata.property.metadata_factory" />
             <argument type="tagged" tag="api_platform.doctrine.orm.query_extension.collection" />
             <argument type="tagged" tag="api_platform.doctrine.orm.query_extension.item" />
         </service>
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/graphql.xml b/src/Bridge/Symfony/Bundle/Resources/config/graphql.xml
index 48638b0e99a..f14b7b328a8 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/graphql.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/graphql.xml
@@ -216,7 +216,6 @@
             <argument type="service" id="api_platform.name_converter" on-invalid="ignore" />
             <argument type="service" id="serializer.mapping.class_metadata_factory" on-invalid="ignore" />
             <argument type="service" id="api_platform.item_data_provider" on-invalid="ignore" />
-            <argument>%api_platform.allow_plain_identifiers%</argument>
             <argument>null</argument>
             <argument type="tagged" tag="api_platform.data_transformer" on-invalid="ignore" />
             <argument type="service" id="api_platform.metadata.resource.metadata_factory" on-invalid="ignore" />
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/hal.xml b/src/Bridge/Symfony/Bundle/Resources/config/hal.xml
index 9ba48f25be3..74ccc77d146 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/hal.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/hal.xml
@@ -37,7 +37,6 @@
             <argument type="service" id="api_platform.name_converter" on-invalid="ignore" />
             <argument type="service" id="serializer.mapping.class_metadata_factory" on-invalid="ignore" />
             <argument>null</argument>
-            <argument>false</argument>
             <argument type="collection" />
             <argument type="tagged" tag="api_platform.data_transformer" on-invalid="ignore" />
             <argument type="service" id="api_platform.metadata.resource.metadata_factory" on-invalid="ignore" />
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/openapi.xml b/src/Bridge/Symfony/Bundle/Resources/config/openapi.xml
index 03bda2f24da..604b37ec366 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/openapi.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/openapi.xml
@@ -39,6 +39,7 @@
             <argument>%api_platform.formats%</argument>
             <argument type="service" id="api_platform.openapi.options" />
             <argument type="service" id="api_platform.pagination_options" />
+            <argument type="service" id="api_platform.identifiers_extractor.cached" />
         </service>
         <service id="ApiPlatform\Core\OpenApi\Factory\OpenApiFactoryInterface" alias="api_platform.openapi.factory" />
 
diff --git a/src/Bridge/Symfony/Bundle/Resources/config/swagger.xml b/src/Bridge/Symfony/Bundle/Resources/config/swagger.xml
index df28ac3f8fc..f41fb55c44e 100644
--- a/src/Bridge/Symfony/Bundle/Resources/config/swagger.xml
+++ b/src/Bridge/Symfony/Bundle/Resources/config/swagger.xml
@@ -33,6 +33,7 @@
             <argument>%api_platform.collection.pagination.enabled_parameter_name%</argument>
             <argument type="collection" />
             <argument>%api_platform.swagger.versions%</argument>
+            <argument type="service" id="api_platform.identifiers_extractor.cached" />
             <tag name="serializer.normalizer" priority="-790" />
         </service>
 
diff --git a/src/Bridge/Symfony/Routing/ApiLoader.php b/src/Bridge/Symfony/Routing/ApiLoader.php
index 3bdad5ac363..17b886ac4c0 100644
--- a/src/Bridge/Symfony/Routing/ApiLoader.php
+++ b/src/Bridge/Symfony/Routing/ApiLoader.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Bridge\Symfony\Routing;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\OperationType;
 use ApiPlatform\Core\Exception\InvalidResourceException;
 use ApiPlatform\Core\Exception\RuntimeException;
@@ -56,8 +57,9 @@ final class ApiLoader extends Loader
     private $graphQlPlaygroundEnabled;
     private $entrypointEnabled;
     private $docsEnabled;
+    private $identifiersExtractor;
 
-    public function __construct(KernelInterface $kernel, ResourceNameCollectionFactoryInterface $resourceNameCollectionFactory, ResourceMetadataFactoryInterface $resourceMetadataFactory, OperationPathResolverInterface $operationPathResolver, ContainerInterface $container, array $formats, array $resourceClassDirectories = [], SubresourceOperationFactoryInterface $subresourceOperationFactory = null, bool $graphqlEnabled = false, bool $entrypointEnabled = true, bool $docsEnabled = true, bool $graphiQlEnabled = false, bool $graphQlPlaygroundEnabled = false)
+    public function __construct(KernelInterface $kernel, ResourceNameCollectionFactoryInterface $resourceNameCollectionFactory, ResourceMetadataFactoryInterface $resourceMetadataFactory, OperationPathResolverInterface $operationPathResolver, ContainerInterface $container, array $formats, array $resourceClassDirectories = [], SubresourceOperationFactoryInterface $subresourceOperationFactory = null, bool $graphqlEnabled = false, bool $entrypointEnabled = true, bool $docsEnabled = true, bool $graphiQlEnabled = false, bool $graphQlPlaygroundEnabled = false, IdentifiersExtractorInterface $identifiersExtractor)
     {
         /** @var string[]|string $paths */
         $paths = $kernel->locateResource('@ApiPlatformBundle/Resources/config/routing');
@@ -74,6 +76,7 @@ public function __construct(KernelInterface $kernel, ResourceNameCollectionFacto
         $this->graphQlPlaygroundEnabled = $graphQlPlaygroundEnabled;
         $this->entrypointEnabled = $entrypointEnabled;
         $this->docsEnabled = $docsEnabled;
+        $this->identifiersExtractor = $identifiersExtractor;
     }
 
     /**
@@ -90,6 +93,7 @@ public function load($data, $type = null): RouteCollection
 
         foreach ($this->resourceNameCollectionFactory->create() as $resourceClass) {
             $resourceMetadata = $this->resourceMetadataFactory->create($resourceClass);
+            $resourceMetadata = $resourceMetadata->withAttributes(($resourceMetadata->getAttributes() ?: []) + ['identified_by' => $this->identifiersExtractor->getIdentifiersFromResourceClass($resourceClass)]);
             $resourceShortName = $resourceMetadata->getShortName();
 
             if (null === $resourceShortName) {
@@ -128,6 +132,8 @@ public function load($data, $type = null): RouteCollection
                         '_format' => null,
                         '_stateless' => $operation['stateless'] ?? $resourceMetadata->getAttribute('stateless'),
                         '_api_resource_class' => $operation['resource_class'],
+                        '_api_identified_by' => $operation['identified_by'],
+                        '_api_has_composite_identifier' => false,
                         '_api_subresource_operation_name' => $operation['route_name'],
                         '_api_subresource_context' => [
                             'property' => $operation['property'],
@@ -222,6 +228,9 @@ private function addRoute(RouteCollection $routeCollection, string $resourceClas
             }
         }
 
+        $operation['identified_by'] = (array) ($operation['identified_by'] ?? $resourceMetadata->getAttribute('identified_by'));
+        $operation['has_composite_identifier'] = \count($operation['identified_by']) > 1 ? $resourceMetadata->getAttribute('composite_identifier', true) : false;
+
         $path = trim(trim($resourceMetadata->getAttribute('route_prefix', '')), '/');
         $path .= $this->operationPathResolver->resolveOperationPath($resourceShortName, $operation, $operationType, $operationName);
 
@@ -232,6 +241,8 @@ private function addRoute(RouteCollection $routeCollection, string $resourceClas
                 '_format' => null,
                 '_stateless' => $operation['stateless'],
                 '_api_resource_class' => $resourceClass,
+                '_api_identified_by' => $operation['identified_by'],
+                '_api_has_composite_identifier' => $operation['has_composite_identifier'],
                 sprintf('_api_%s_operation_name', $operationType) => $operationName,
             ] + ($operation['defaults'] ?? []),
             $operation['requirements'] ?? [],
diff --git a/src/Bridge/Symfony/Routing/IriConverter.php b/src/Bridge/Symfony/Routing/IriConverter.php
index e0c8e5c7211..7f34c562de4 100644
--- a/src/Bridge/Symfony/Routing/IriConverter.php
+++ b/src/Bridge/Symfony/Routing/IriConverter.php
@@ -13,7 +13,6 @@
 
 namespace ApiPlatform\Core\Bridge\Symfony\Routing;
 
-use ApiPlatform\Core\Api\IdentifiersExtractor;
 use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\IriConverterInterface;
 use ApiPlatform\Core\Api\OperationType;
@@ -26,14 +25,11 @@
 use ApiPlatform\Core\Exception\InvalidIdentifierException;
 use ApiPlatform\Core\Exception\ItemNotFoundException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
+use ApiPlatform\Core\Identifier\CompositeIdentifierParser;
+use ApiPlatform\Core\Identifier\IdentifierDenormalizerInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
 use ApiPlatform\Core\Util\AttributesExtractor;
 use ApiPlatform\Core\Util\ResourceClassInfoTrait;
-use Symfony\Component\PropertyAccess\PropertyAccess;
-use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
 use Symfony\Component\Routing\Exception\ExceptionInterface as RoutingExceptionInterface;
 use Symfony\Component\Routing\RouterInterface;
 
@@ -51,20 +47,16 @@ final class IriConverter implements IriConverterInterface
     private $router;
     private $identifiersExtractor;
 
-    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, ItemDataProviderInterface $itemDataProvider, RouteNameResolverInterface $routeNameResolver, RouterInterface $router, PropertyAccessorInterface $propertyAccessor = null, IdentifiersExtractorInterface $identifiersExtractor = null, SubresourceDataProviderInterface $subresourceDataProvider = null, IdentifierConverterInterface $identifierConverter = null, ResourceClassResolverInterface $resourceClassResolver = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
+    public function __construct(ItemDataProviderInterface $itemDataProvider, RouteNameResolverInterface $routeNameResolver, RouterInterface $router, IdentifiersExtractorInterface $identifiersExtractor, SubresourceDataProviderInterface $subresourceDataProvider = null, IdentifierDenormalizerInterface $identifierDenormalizer = null, ResourceClassResolverInterface $resourceClassResolver = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
     {
         $this->itemDataProvider = $itemDataProvider;
         $this->routeNameResolver = $routeNameResolver;
         $this->router = $router;
         $this->identifiersExtractor = $identifiersExtractor;
         $this->subresourceDataProvider = $subresourceDataProvider;
-        $this->identifierConverter = $identifierConverter;
+        $this->identifierDenormalizer = $identifierDenormalizer;
         $this->resourceClassResolver = $resourceClassResolver;
-
-        if (null === $identifiersExtractor) {
-            @trigger_error(sprintf('Not injecting "%s" is deprecated since API Platform 2.1 and will not be possible anymore in API Platform 3', IdentifiersExtractorInterface::class), E_USER_DEPRECATED);
-            $this->identifiersExtractor = new IdentifiersExtractor($propertyNameCollectionFactory, $propertyMetadataFactory, $propertyAccessor ?? PropertyAccess::createPropertyAccessor());
-        }
+        $this->identifiersExtractor = $identifiersExtractor;
         $this->resourceMetadataFactory = $resourceMetadataFactory;
     }
 
@@ -95,10 +87,6 @@ public function getItemFromIri(string $iri, array $context = [])
             throw new InvalidArgumentException($e->getMessage(), $e->getCode(), $e);
         }
 
-        if ($this->identifierConverter) {
-            $context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] = true;
-        }
-
         if (isset($attributes['subresource_operation_name'])) {
             if (($item = $this->getSubresourceData($identifiers, $attributes, $context)) && !\is_array($item)) {
                 return $item;
@@ -148,11 +136,14 @@ public function getIriFromResourceClass(string $resourceClass, int $referenceTyp
     public function getItemIriFromResourceClass(string $resourceClass, array $identifiers, int $referenceType = null): string
     {
         $routeName = $this->routeNameResolver->getRouteName($resourceClass, OperationType::ITEM);
+        $metadata = $this->resourceMetadataFactory->create($resourceClass);
 
-        try {
-            $identifiers = $this->generateIdentifiersUrl($identifiers, $resourceClass);
+        if (\count($identifiers) > 1 && true === $metadata->getAttribute('composite_identifier', true)) {
+            $identifiers = ['id' => CompositeIdentifierParser::stringify($identifiers)];
+        }
 
-            return $this->router->generate($routeName, ['id' => implode(';', $identifiers)], $this->getReferenceType($resourceClass, $referenceType));
+        try {
+            return $this->router->generate($routeName, $identifiers, $this->getReferenceType($resourceClass, $referenceType));
         } catch (RoutingExceptionInterface $e) {
             throw new InvalidArgumentException(sprintf('Unable to generate an IRI for "%s".', $resourceClass), $e->getCode(), $e);
         }
@@ -170,30 +161,6 @@ public function getSubresourceIriFromResourceClass(string $resourceClass, array
         }
     }
 
-    /**
-     * Generate the identifier url.
-     *
-     * @throws InvalidArgumentException
-     *
-     * @return string[]
-     */
-    private function generateIdentifiersUrl(array $identifiers, string $resourceClass): array
-    {
-        if (0 === \count($identifiers)) {
-            throw new InvalidArgumentException(sprintf('No identifiers defined for resource of type "%s"', $resourceClass));
-        }
-
-        if (1 === \count($identifiers)) {
-            return [(string) reset($identifiers)];
-        }
-
-        foreach ($identifiers as $name => $value) {
-            $identifiers[$name] = sprintf('%s=%s', $name, $value);
-        }
-
-        return array_values($identifiers);
-    }
-
     private function getReferenceType(string $resourceClass, ?int $referenceType): ?int
     {
         if (null === $referenceType && null !== $this->resourceMetadataFactory) {
diff --git a/src/DataProvider/ChainItemDataProvider.php b/src/DataProvider/ChainItemDataProvider.php
index defb799f7fa..35a20c7e8f2 100644
--- a/src/DataProvider/ChainItemDataProvider.php
+++ b/src/DataProvider/ChainItemDataProvider.php
@@ -40,7 +40,7 @@ public function __construct(iterable $dataProviders)
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         foreach ($this->dataProviders as $dataProvider) {
             try {
@@ -49,17 +49,7 @@ public function getItem(string $resourceClass, $id, string $operationName = null
                     continue;
                 }
 
-                $identifier = $id;
-                if (!$dataProvider instanceof DenormalizedIdentifiersAwareItemDataProviderInterface && $identifier && \is_array($identifier)) {
-                    if (\count($identifier) > 1) {
-                        @trigger_error(sprintf('Receiving "$id" as non-array in an item data provider is deprecated in 2.3 in favor of implementing "%s".', DenormalizedIdentifiersAwareItemDataProviderInterface::class), E_USER_DEPRECATED);
-                        $identifier = http_build_query($identifier, '', ';');
-                    } else {
-                        $identifier = current($identifier);
-                    }
-                }
-
-                return $dataProvider->getItem($resourceClass, $identifier, $operationName, $context);
+                return $dataProvider->getItem($resourceClass, $identifiers, $operationName, $context);
             } catch (ResourceClassNotSupportedException $e) {
                 @trigger_error(sprintf('Throwing a "%s" is deprecated in favor of implementing "%s"', \get_class($e), RestrictedDataProviderInterface::class), E_USER_DEPRECATED);
                 continue;
diff --git a/src/DataProvider/DenormalizedIdentifiersAwareItemDataProviderInterface.php b/src/DataProvider/DenormalizedIdentifiersAwareItemDataProviderInterface.php
deleted file mode 100644
index 07067dc0b25..00000000000
--- a/src/DataProvider/DenormalizedIdentifiersAwareItemDataProviderInterface.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-/*
- * This file is part of the API Platform project.
- *
- * (c) Kévin Dunglas <dunglas@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-declare(strict_types=1);
-
-namespace ApiPlatform\Core\DataProvider;
-
-/**
- * Marks data providers able to deal with complex identifiers denormalized as an array.
- *
- * @author Anthony GRASSIOT <antograssiot@free.Fr>
- */
-interface DenormalizedIdentifiersAwareItemDataProviderInterface extends ItemDataProviderInterface
-{
-    /**
-     * {@inheritdoc}
-     */
-    public function getItem(string $resourceClass, /* array */ $id, string $operationName = null, array $context = []);
-}
diff --git a/src/DataProvider/ItemDataProviderInterface.php b/src/DataProvider/ItemDataProviderInterface.php
index 050cdceee1b..aeba9e9797d 100644
--- a/src/DataProvider/ItemDataProviderInterface.php
+++ b/src/DataProvider/ItemDataProviderInterface.php
@@ -25,11 +25,9 @@ interface ItemDataProviderInterface
     /**
      * Retrieves an item.
      *
-     * @param array|int|string $id
-     *
      * @throws ResourceClassNotSupportedException
      *
      * @return object|null
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = []);
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = []);
 }
diff --git a/src/DataProvider/OperationDataProviderTrait.php b/src/DataProvider/OperationDataProviderTrait.php
index f08521ce379..a3e1cb7367f 100644
--- a/src/DataProvider/OperationDataProviderTrait.php
+++ b/src/DataProvider/OperationDataProviderTrait.php
@@ -15,7 +15,8 @@
 
 use ApiPlatform\Core\Exception\InvalidIdentifierException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
+use ApiPlatform\Core\Identifier\CompositeIdentifierParser;
+use ApiPlatform\Core\Identifier\IdentifierDenormalizerInterface;
 
 /**
  * @internal
@@ -38,9 +39,9 @@ trait OperationDataProviderTrait
     private $subresourceDataProvider;
 
     /**
-     * @var IdentifierConverterInterface|null
+     * @var IdentifierDenormalizerInterface
      */
-    private $identifierConverter;
+    private $identifierDenormalizer;
 
     /**
      * Retrieves data for a collection operation.
@@ -75,7 +76,18 @@ private function getSubresourceData($identifiers, array $attributes, array $cont
             throw new RuntimeException('Subresources not supported');
         }
 
-        return $this->subresourceDataProvider->getSubresource($attributes['resource_class'], $identifiers, $attributes['subresource_context'] + $context, $attributes['subresource_operation_name']);
+        $subresourceIdentifiers = [];
+        foreach ($attributes['subresource_context']['identifiers'] as list($identifier, , $isItem, $identifiedBy)) {
+            if ($isItem) {
+                $subresourceIdentifiers[$identifier] = [$identifiedBy[0] => current($identifiers)];
+                next($identifiers);
+                continue;
+            }
+
+            $subresourceIdentifiers[$identifier] = [];
+        }
+
+        return $this->subresourceDataProvider->getSubresource($attributes['resource_class'], $subresourceIdentifiers, $attributes['subresource_context'] + $context, $attributes['subresource_operation_name']);
     }
 
     /**
@@ -85,38 +97,38 @@ private function getSubresourceData($identifiers, array $attributes, array $cont
      */
     private function extractIdentifiers(array $parameters, array $attributes)
     {
-        if (isset($attributes['item_operation_name'])) {
-            if (!isset($parameters['id'])) {
-                throw new InvalidIdentifierException('Parameter "id" not found');
-            }
-
-            $id = $parameters['id'];
+        $identifiersKeys = $attributes['identified_by'] ?? [];
+        $identifiers = [];
 
-            if (null !== $this->identifierConverter) {
-                return $this->identifierConverter->convert((string) $id, $attributes['resource_class']);
+        if (isset($attributes['subresource_context'])) {
+            $subresourceIdentifiersKeys = [];
+            $i = 0;
+            foreach ($attributes['subresource_context']['identifiers'] as list($identifier, , $isItem)) {
+                if ($isItem) {
+                    $subresourceIdentifiersKeys[] = $identifiersKeys[$i++] ?? $identifier;
+                }
             }
-
-            return $id;
+            $identifiersKeys = $subresourceIdentifiersKeys;
         }
 
-        if (!isset($attributes['subresource_context'])) {
-            throw new RuntimeException('Either "item_operation_name" or "collection_operation_name" must be defined, unless the "_api_receive" request attribute is set to false.');
-        }
+        $identifiersNumber = \count($identifiersKeys);
+        foreach ($identifiersKeys as $identifier) {
+            if (!isset($parameters[$identifier])) {
+                if ($attributes['has_composite_identifier']) {
+                    $identifiers = CompositeIdentifierParser::parse($parameters['id']);
+                    if (($currentIdentifiersNumber = \count($identifiers)) !== $identifiersNumber) {
+                        throw new InvalidIdentifierException(sprintf('Expected %d identifiers, got %d', $identifiersNumber, $currentIdentifiersNumber));
+                    }
 
-        $identifiers = [];
+                    return $identifiers;
+                }
 
-        foreach ($attributes['subresource_context']['identifiers'] as $key => [$id, $resourceClass, $hasIdentifier]) {
-            if (false === $hasIdentifier) {
-                continue;
+                throw new InvalidIdentifierException(sprintf('Parameter "%s" not found', $identifier));
             }
 
-            $identifiers[$id] = $parameters[$id];
-
-            if (null !== $this->identifierConverter) {
-                $identifiers[$id] = $this->identifierConverter->convert((string) $identifiers[$id], $resourceClass);
-            }
+            $identifiers[$identifier] = $parameters[$identifier];
         }
 
-        return $identifiers;
+        return $this->identifierDenormalizer->denormalize($identifiers, $attributes['resource_class']);
     }
 }
diff --git a/src/EventListener/ReadListener.php b/src/EventListener/ReadListener.php
index 87dbe3e945f..c8a6963456e 100644
--- a/src/EventListener/ReadListener.php
+++ b/src/EventListener/ReadListener.php
@@ -19,7 +19,7 @@
 use ApiPlatform\Core\DataProvider\SubresourceDataProviderInterface;
 use ApiPlatform\Core\Exception\InvalidIdentifierException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
+use ApiPlatform\Core\Identifier\IdentifierDenormalizerInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\ToggleableOperationAttributeTrait;
 use ApiPlatform\Core\Serializer\SerializerContextBuilderInterface;
@@ -44,13 +44,13 @@ final class ReadListener
 
     private $serializerContextBuilder;
 
-    public function __construct(CollectionDataProviderInterface $collectionDataProvider, ItemDataProviderInterface $itemDataProvider, SubresourceDataProviderInterface $subresourceDataProvider = null, SerializerContextBuilderInterface $serializerContextBuilder = null, IdentifierConverterInterface $identifierConverter = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
+    public function __construct(CollectionDataProviderInterface $collectionDataProvider, ItemDataProviderInterface $itemDataProvider, SubresourceDataProviderInterface $subresourceDataProvider = null, SerializerContextBuilderInterface $serializerContextBuilder = null, IdentifierDenormalizerInterface $identifierDenormalizer = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
     {
         $this->collectionDataProvider = $collectionDataProvider;
         $this->itemDataProvider = $itemDataProvider;
         $this->subresourceDataProvider = $subresourceDataProvider;
         $this->serializerContextBuilder = $serializerContextBuilder;
-        $this->identifierConverter = $identifierConverter;
+        $this->identifierDenormalizer = $identifierDenormalizer;
         $this->resourceMetadataFactory = $resourceMetadataFactory;
     }
 
@@ -91,10 +91,6 @@ public function onKernelRequest(RequestEvent $event): void
 
         $data = [];
 
-        if ($this->identifierConverter) {
-            $context[IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER] = true;
-        }
-
         try {
             $identifiers = $this->extractIdentifiers($request->attributes->all(), $attributes);
 
diff --git a/src/GraphQl/Serializer/ItemNormalizer.php b/src/GraphQl/Serializer/ItemNormalizer.php
index e7c5e6c8a0c..1103c42f02f 100644
--- a/src/GraphQl/Serializer/ItemNormalizer.php
+++ b/src/GraphQl/Serializer/ItemNormalizer.php
@@ -45,9 +45,9 @@ final class ItemNormalizer extends BaseItemNormalizer
 
     private $identifiersExtractor;
 
-    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, IdentifiersExtractorInterface $identifiersExtractor, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, bool $allowPlainIdentifiers = false, LoggerInterface $logger = null, iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
+    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, IdentifiersExtractorInterface $identifiersExtractor, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, LoggerInterface $logger = null, iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
     {
-        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, $itemDataProvider, $allowPlainIdentifiers, $logger ?: new NullLogger(), $dataTransformers, $resourceMetadataFactory);
+        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, $itemDataProvider, $logger ?: new NullLogger(), $dataTransformers, $resourceMetadataFactory);
 
         $this->identifiersExtractor = $identifiersExtractor;
     }
diff --git a/src/Identifier/CompositeIdentifierParser.php b/src/Identifier/CompositeIdentifierParser.php
index 3aa72c79bde..80306a39f17 100644
--- a/src/Identifier/CompositeIdentifierParser.php
+++ b/src/Identifier/CompositeIdentifierParser.php
@@ -20,6 +20,8 @@
  */
 final class CompositeIdentifierParser
 {
+    public const COMPOSITE_IDENTIFIER_REGEXP = '/(\w+)=(?<=\w=)(.*?)(?=;\w+=)|(\w+)=([^;]*);?$/';
+
     private function __construct()
     {
     }
@@ -33,7 +35,7 @@ public static function parse(string $identifier): array
     {
         $matches = [];
         $identifiers = [];
-        $num = preg_match_all('/(\w+)=(?<=\w=)(.*?)(?=;\w+=)|(\w+)=([^;]*);?$/', $identifier, $matches, PREG_SET_ORDER);
+        $num = preg_match_all(self::COMPOSITE_IDENTIFIER_REGEXP, $identifier, $matches, PREG_SET_ORDER);
 
         foreach ($matches as $i => $match) {
             if ($i === $num - 1) {
@@ -45,4 +47,14 @@ public static function parse(string $identifier): array
 
         return $identifiers;
     }
+
+    public static function stringify(array $identifiers): string
+    {
+        $composite = [];
+        foreach ($identifiers as $name => $value) {
+            $composite[] = sprintf('%s=%s', $name, $value);
+        }
+
+        return implode(';', $composite);
+    }
 }
diff --git a/src/Identifier/IdentifierConverter.php b/src/Identifier/IdentifierConverter.php
deleted file mode 100644
index 9faafd8ef54..00000000000
--- a/src/Identifier/IdentifierConverter.php
+++ /dev/null
@@ -1,100 +0,0 @@
-<?php
-
-/*
- * This file is part of the API Platform project.
- *
- * (c) Kévin Dunglas <dunglas@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-declare(strict_types=1);
-
-namespace ApiPlatform\Core\Identifier;
-
-use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
-use ApiPlatform\Core\Exception\InvalidIdentifierException;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
-use Symfony\Component\PropertyInfo\Type;
-use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
-
-/**
- * Identifier converter that chains identifier denormalizers.
- *
- * @author Antoine Bluchet <soyuka@gmail.com>
- */
-final class IdentifierConverter implements ContextAwareIdentifierConverterInterface
-{
-    private $propertyMetadataFactory;
-    private $identifiersExtractor;
-    private $identifierDenormalizers;
-    private $resourceMetadataFactory;
-
-    /**
-     * @param iterable<DenormalizerInterface> $identifierDenormalizers
-     */
-    public function __construct(IdentifiersExtractorInterface $identifiersExtractor, PropertyMetadataFactoryInterface $propertyMetadataFactory, iterable $identifierDenormalizers, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
-    {
-        $this->propertyMetadataFactory = $propertyMetadataFactory;
-        $this->identifiersExtractor = $identifiersExtractor;
-        $this->identifierDenormalizers = $identifierDenormalizers;
-        $this->resourceMetadataFactory = $resourceMetadataFactory;
-    }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function convert(string $data, string $class, array $context = []): array
-    {
-        if (null !== $this->resourceMetadataFactory) {
-            $resourceMetadata = $this->resourceMetadataFactory->create($class);
-            $class = $resourceMetadata->getOperationAttribute($context, 'output', ['class' => $class], true)['class'];
-        }
-
-        $keys = $this->identifiersExtractor->getIdentifiersFromResourceClass($class);
-
-        if (($numIdentifiers = \count($keys)) > 1) {
-            $identifiers = CompositeIdentifierParser::parse($data);
-        } elseif (0 === $numIdentifiers) {
-            throw new InvalidIdentifierException(sprintf('Resource "%s" has no identifiers.', $class));
-        } else {
-            $identifiers = [$keys[0] => $data];
-        }
-
-        // Normalize every identifier (DateTime, UUID etc.)
-        foreach ($keys as $key) {
-            if (!isset($identifiers[$key])) {
-                throw new InvalidIdentifierException(sprintf('Invalid identifier "%1$s", "%1$s" was not found.', $key));
-            }
-
-            if (null === $type = $this->getIdentifierType($class, $key)) {
-                continue;
-            }
-
-            foreach ($this->identifierDenormalizers as $identifierDenormalizer) {
-                if (!$identifierDenormalizer->supportsDenormalization($identifiers[$key], $type)) {
-                    continue;
-                }
-
-                try {
-                    $identifiers[$key] = $identifierDenormalizer->denormalize($identifiers[$key], $type);
-                } catch (InvalidIdentifierException $e) {
-                    throw new InvalidIdentifierException(sprintf('Identifier "%s" could not be denormalized.', $key), $e->getCode(), $e);
-                }
-            }
-        }
-
-        return $identifiers;
-    }
-
-    private function getIdentifierType(string $resourceClass, string $property): ?string
-    {
-        if (!$type = $this->propertyMetadataFactory->create($resourceClass, $property)->getType()) {
-            return null;
-        }
-
-        return Type::BUILTIN_TYPE_OBJECT === ($builtinType = $type->getBuiltinType()) ? $type->getClassName() : $builtinType;
-    }
-}
diff --git a/src/Identifier/IdentifierConverterInterface.php b/src/Identifier/IdentifierConverterInterface.php
deleted file mode 100644
index 93962a2d47d..00000000000
--- a/src/Identifier/IdentifierConverterInterface.php
+++ /dev/null
@@ -1,39 +0,0 @@
-<?php
-
-/*
- * This file is part of the API Platform project.
- *
- * (c) Kévin Dunglas <dunglas@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-declare(strict_types=1);
-
-namespace ApiPlatform\Core\Identifier;
-
-use ApiPlatform\Core\Exception\InvalidIdentifierException;
-
-/**
- * Identifier converter.
- *
- * @author Antoine Bluchet <soyuka@gmail.com>
- */
-interface IdentifierConverterInterface
-{
-    /**
-     * @internal
-     */
-    public const HAS_IDENTIFIER_CONVERTER = 'has_identifier_converter';
-
-    /**
-     * @param string $data  Identifier to convert to php values
-     * @param string $class The class to which the identifiers belong
-     *
-     * @throws InvalidIdentifierException
-     *
-     * @return array Indexed by identifiers properties with their values denormalized
-     */
-    public function convert(string $data, string $class): array;
-}
diff --git a/src/Identifier/IdentifierDenormalizer.php b/src/Identifier/IdentifierDenormalizer.php
new file mode 100644
index 00000000000..0c86806bb63
--- /dev/null
+++ b/src/Identifier/IdentifierDenormalizer.php
@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Identifier;
+
+use ApiPlatform\Core\Exception\InvalidIdentifierException;
+use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
+use Symfony\Component\PropertyInfo\Type;
+use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
+
+/**
+ * Identifier denormalizer.
+ *
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ */
+final class IdentifierDenormalizer implements IdentifierDenormalizerInterface
+{
+    private $propertyMetadataFactory;
+    private $identifierDenormalizers;
+
+    /**
+     * @param iterable<DenormalizerInterface> $identifierDenormalizers
+     */
+    public function __construct(PropertyMetadataFactoryInterface $propertyMetadataFactory, iterable $identifierDenormalizers)
+    {
+        $this->propertyMetadataFactory = $propertyMetadataFactory;
+        $this->identifierDenormalizers = $identifierDenormalizers;
+    }
+
+    /*
+     * {@inheritdoc}
+     */
+    public function denormalize($identifiers, $class, ?string $format = null, array $context = []): array
+    {
+        foreach ($identifiers as $identifier => $value) {
+            if (null === $type = $this->getIdentifierType($class, $identifier)) {
+                continue;
+            }
+
+            foreach ($this->identifierDenormalizers as $identifierDenormalizer) {
+                if (!$identifierDenormalizer->supportsDenormalization($value, $type)) {
+                    continue;
+                }
+
+                try {
+                    $identifiers[$identifier] = $identifierDenormalizer->denormalize($value, $type);
+                } catch (InvalidIdentifierException $e) {
+                    throw new InvalidIdentifierException(sprintf('Identifier "%s" could not be denormalized.', $identifier), $e->getCode(), $e);
+                }
+            }
+        }
+
+        return $identifiers;
+    }
+
+    private function getIdentifierType(string $resourceClass, string $property): ?string
+    {
+        if (!$type = $this->propertyMetadataFactory->create($resourceClass, $property)->getType()) {
+            return null;
+        }
+
+        return Type::BUILTIN_TYPE_OBJECT === ($builtinType = $type->getBuiltinType()) ? $type->getClassName() : $builtinType;
+    }
+}
diff --git a/src/Identifier/ContextAwareIdentifierConverterInterface.php b/src/Identifier/IdentifierDenormalizerInterface.php
similarity index 51%
rename from src/Identifier/ContextAwareIdentifierConverterInterface.php
rename to src/Identifier/IdentifierDenormalizerInterface.php
index 83675089eb0..ce595f18fb6 100644
--- a/src/Identifier/ContextAwareIdentifierConverterInterface.php
+++ b/src/Identifier/IdentifierDenormalizerInterface.php
@@ -13,15 +13,10 @@
 
 namespace ApiPlatform\Core\Identifier;
 
-/**
- * Gives access to the context in the IdentifierConverter.
- *
- * @author Antoine Bluchet <soyuka@gmail.com>
- */
-interface ContextAwareIdentifierConverterInterface extends IdentifierConverterInterface
+interface IdentifierDenormalizerInterface
 {
     /**
-     * {@inheritdoc}
+     * Takes an array of identifiers and transform their values from strings to the expected type.
      */
-    public function convert(string $data, string $class, array $context = []): array;
+    public function denormalize($identifiers, $class, ?string $format = null, array $context = []): array;
 }
diff --git a/src/JsonApi/Serializer/ItemNormalizer.php b/src/JsonApi/Serializer/ItemNormalizer.php
index ade96fe723c..3eada3db3ec 100644
--- a/src/JsonApi/Serializer/ItemNormalizer.php
+++ b/src/JsonApi/Serializer/ItemNormalizer.php
@@ -52,7 +52,7 @@ final class ItemNormalizer extends AbstractItemNormalizer
 
     public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, ?PropertyAccessorInterface $propertyAccessor, ?NameConverterInterface $nameConverter, ResourceMetadataFactoryInterface $resourceMetadataFactory, array $defaultContext = [], iterable $dataTransformers = [], ResourceAccessCheckerInterface $resourceAccessChecker = null)
     {
-        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, null, null, false, $defaultContext, $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
+        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, null, null, $defaultContext, $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
     }
 
     /**
diff --git a/src/JsonLd/Serializer/ItemNormalizer.php b/src/JsonLd/Serializer/ItemNormalizer.php
index 793eba67639..2fc276d1dec 100644
--- a/src/JsonLd/Serializer/ItemNormalizer.php
+++ b/src/JsonLd/Serializer/ItemNormalizer.php
@@ -46,7 +46,7 @@ final class ItemNormalizer extends AbstractItemNormalizer
 
     public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, ContextBuilderInterface $contextBuilder, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, array $defaultContext = [], iterable $dataTransformers = [], ResourceAccessCheckerInterface $resourceAccessChecker = null)
     {
-        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, null, false, $defaultContext, $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
+        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, null, $defaultContext, $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
 
         $this->contextBuilder = $contextBuilder;
     }
diff --git a/src/OpenApi/Factory/OpenApiFactory.php b/src/OpenApi/Factory/OpenApiFactory.php
index 7ce8cc4d137..69238100fb1 100644
--- a/src/OpenApi/Factory/OpenApiFactory.php
+++ b/src/OpenApi/Factory/OpenApiFactory.php
@@ -14,6 +14,7 @@
 namespace ApiPlatform\Core\OpenApi\Factory;
 
 use ApiPlatform\Core\Api\FilterLocatorTrait;
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\OperationType;
 use ApiPlatform\Core\DataProvider\PaginationOptions;
 use ApiPlatform\Core\JsonSchema\Schema;
@@ -53,8 +54,9 @@ final class OpenApiFactory implements OpenApiFactoryInterface
     private $jsonSchemaTypeFactory;
     private $openApiOptions;
     private $paginationOptions;
+    private $identifiersExtractor;
 
-    public function __construct(ResourceNameCollectionFactoryInterface $resourceNameCollectionFactory, ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, SchemaFactoryInterface $jsonSchemaFactory, TypeFactoryInterface $jsonSchemaTypeFactory, OperationPathResolverInterface $operationPathResolver, ContainerInterface $filterLocator, SubresourceOperationFactoryInterface $subresourceOperationFactory, array $formats = [], Options $openApiOptions, PaginationOptions $paginationOptions)
+    public function __construct(ResourceNameCollectionFactoryInterface $resourceNameCollectionFactory, ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, SchemaFactoryInterface $jsonSchemaFactory, TypeFactoryInterface $jsonSchemaTypeFactory, OperationPathResolverInterface $operationPathResolver, ContainerInterface $filterLocator, SubresourceOperationFactoryInterface $subresourceOperationFactory, array $formats = [], Options $openApiOptions, PaginationOptions $paginationOptions, IdentifiersExtractorInterface $identifiersExtractor)
     {
         $this->resourceNameCollectionFactory = $resourceNameCollectionFactory;
         $this->jsonSchemaFactory = $jsonSchemaFactory;
@@ -68,6 +70,7 @@ public function __construct(ResourceNameCollectionFactoryInterface $resourceName
         $this->openApiOptions = $openApiOptions;
         $this->paginationOptions = $paginationOptions;
         $this->subresourceOperationFactory = $subresourceOperationFactory;
+        $this->identifiersExtractor = $identifiersExtractor;
     }
 
     /**
@@ -84,6 +87,7 @@ public function __invoke(array $context = []): OpenApi
 
         foreach ($this->resourceNameCollectionFactory->create() as $resourceClass) {
             $resourceMetadata = $this->resourceMetadataFactory->create($resourceClass);
+            $resourceMetadata = $resourceMetadata->withAttributes(($resourceMetadata->getAttributes() ?: []) + ['identified_by' => $this->identifiersExtractor->getIdentifiersFromResourceClass($resourceClass)]);
             $resourceShortName = $resourceMetadata->getShortName();
 
             // Items needs to be parsed first to be able to reference the lines from the collection operation
@@ -117,6 +121,13 @@ private function collectPaths(ResourceMetadata $resourceMetadata, string $resour
         }
 
         foreach ($operations as $operationName => $operation) {
+            $identifiers = (array) ($operation['identified_by'] ?? $resourceMetadata->getAttribute('identified_by'));
+            $hasCompositeIdentifiers = \count($identifiers) > 1 ? $resourceMetadata->getAttribute('composite_identifier', true) : false;
+
+            if ($hasCompositeIdentifiers) {
+                $identifiers = ['id'];
+            }
+
             $path = $this->getPath($resourceShortName, $operationName, $operation, $operationType);
             $method = $resourceMetadata->getTypedOperationAttribute($operationType, $operationName, 'method', 'GET');
             list($requestMimeTypes, $responseMimeTypes) = $this->getMimeTypes($resourceClass, $operationName, $operationType, $resourceMetadata);
@@ -136,7 +147,10 @@ private function collectPaths(ResourceMetadata $resourceMetadata, string $resour
 
             // Set up parameters
             if (OperationType::ITEM === $operationType) {
-                $parameters[] = new Model\Parameter('id', 'path', 'Resource identifier', true, false, false, ['type' => 'string']);
+                foreach ($identifiers as $identifier) {
+                    $parameters[] = new Model\Parameter($identifier, 'path', 'Resource identifier', true, false, false, ['type' => 'string']);
+                }
+
                 $links[$operationId] = $this->getLink($resourceClass, $operationId, $path);
             } elseif (OperationType::COLLECTION === $operationType && 'GET' === $method) {
                 $parameters = array_merge($parameters, $this->getPaginationParameters($resourceMetadata, $operationName), $this->getFiltersParameters($resourceMetadata, $operationName, $resourceClass));
diff --git a/src/Operation/Factory/SubresourceOperationFactory.php b/src/Operation/Factory/SubresourceOperationFactory.php
index b6dbd4298e5..fe6c185dc2c 100644
--- a/src/Operation/Factory/SubresourceOperationFactory.php
+++ b/src/Operation/Factory/SubresourceOperationFactory.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Operation\Factory;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Bridge\Symfony\Routing\RouteNameGenerator;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
@@ -32,13 +33,15 @@ final class SubresourceOperationFactory implements SubresourceOperationFactoryIn
     private $propertyNameCollectionFactory;
     private $propertyMetadataFactory;
     private $pathSegmentNameGenerator;
+    private $identifiersExtractor;
 
-    public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, PathSegmentNameGeneratorInterface $pathSegmentNameGenerator)
+    public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, PathSegmentNameGeneratorInterface $pathSegmentNameGenerator, IdentifiersExtractorInterface $identifiersExtractor)
     {
         $this->resourceMetadataFactory = $resourceMetadataFactory;
         $this->propertyNameCollectionFactory = $propertyNameCollectionFactory;
         $this->propertyMetadataFactory = $propertyMetadataFactory;
         $this->pathSegmentNameGenerator = $pathSegmentNameGenerator;
+        $this->identifiersExtractor = $identifiersExtractor;
     }
 
     /**
@@ -75,6 +78,7 @@ private function computeSubresourceOperations(string $resourceClass, array &$tre
 
             $subresourceClass = $subresource->getResourceClass();
             $subresourceMetadata = $this->resourceMetadataFactory->create($subresourceClass);
+            $subresourceMetadata = $subresourceMetadata->withAttributes(($subresourceMetadata->getAttributes() ?: []) + ['identified_by' => $this->identifiersExtractor->getIdentifiersFromResourceClass($subresourceClass)]);
             $isLastItem = ($parentOperation['resource_class'] ?? null) === $resourceClass && $propertyMetadata->isIdentifier();
 
             // A subresource that is also an identifier can't be a start point
@@ -93,17 +97,20 @@ private function computeSubresourceOperations(string $resourceClass, array &$tre
             }
 
             $rootResourceMetadata = $this->resourceMetadataFactory->create($rootResourceClass);
+            $rootResourceMetadata = $rootResourceMetadata->withAttributes(($rootResourceMetadata->getAttributes() ?: []) + ['identified_by' => $this->identifiersExtractor->getIdentifiersFromResourceClass($rootResourceClass)]);
             $operationName = 'get';
             $operation = [
                 'property' => $property,
                 'collection' => $subresource->isCollection(),
+                'identified_by' => (array) $rootResourceMetadata->getAttribute('identified_by'),
                 'resource_class' => $subresourceClass,
                 'shortNames' => [$subresourceMetadata->getShortName()],
             ];
 
             if (null === $parentOperation) {
                 $rootShortname = $rootResourceMetadata->getShortName();
-                $operation['identifiers'] = [['id', $rootResourceClass, true]];
+                // TODO: mutliple identifiers for subresources?
+                $operation['identifiers'] = [[$operation['identified_by'][0], $rootResourceClass, true, $operation['identified_by']]];
                 $operation['operation_name'] = sprintf(
                     '%s_%s%s',
                     RouteNameGenerator::inflector($operation['property'], $operation['collection'] ?? false),
@@ -126,9 +133,10 @@ private function computeSubresourceOperations(string $resourceClass, array &$tre
                 }
 
                 $operation['path'] = $subresourceOperation['path'] ?? sprintf(
-                    '/%s%s/{id}/%s%s',
+                    '/%s%s/{%s}/%s%s',
                     $prefix,
                     $this->pathSegmentNameGenerator->getSegmentName($rootShortname),
+                    $operation['identified_by'][0],
                     $this->pathSegmentNameGenerator->getSegmentName($operation['property'], $operation['collection']),
                     self::FORMAT_SUFFIX
                 );
@@ -139,7 +147,7 @@ private function computeSubresourceOperations(string $resourceClass, array &$tre
             } else {
                 $resourceMetadata = $this->resourceMetadataFactory->create($resourceClass);
                 $operation['identifiers'] = $parentOperation['identifiers'];
-                $operation['identifiers'][] = [$parentOperation['property'], $resourceClass, $isLastItem ? true : $parentOperation['collection']];
+                $operation['identifiers'][] = [$parentOperation['property'], $resourceClass, $isLastItem ? true : $parentOperation['collection'], $operation['identified_by']];
                 $operation['operation_name'] = str_replace(
                     'get'.self::SUBRESOURCE_SUFFIX,
                     RouteNameGenerator::inflector($isLastItem ? 'item' : $property, $operation['collection']).'_get'.self::SUBRESOURCE_SUFFIX,
diff --git a/src/PathResolver/OperationPathResolver.php b/src/PathResolver/OperationPathResolver.php
index aae217f00de..acf07ba6a33 100644
--- a/src/PathResolver/OperationPathResolver.php
+++ b/src/PathResolver/OperationPathResolver.php
@@ -50,7 +50,13 @@ public function resolveOperationPath(string $resourceShortName, array $operation
         $path = '/'.$this->pathSegmentNameGenerator->getSegmentName($resourceShortName);
 
         if (OperationType::ITEM === $operationType) {
-            $path .= '/{id}';
+            if (isset($operation['identified_by']) && (\count($operation['identified_by']) <= 1 || false === ($operation['has_composite_identifier'] ?? true))) {
+                foreach ($operation['identified_by'] as $identifier) {
+                    $path .= sprintf('/{%s}', $identifier);
+                }
+            } else {
+                $path .= '/{id}';
+            }
         }
 
         $path .= '.{_format}';
diff --git a/src/Serializer/AbstractItemNormalizer.php b/src/Serializer/AbstractItemNormalizer.php
index 7fa39d3d4ee..a0a5b9ed957 100644
--- a/src/Serializer/AbstractItemNormalizer.php
+++ b/src/Serializer/AbstractItemNormalizer.php
@@ -19,7 +19,6 @@
 use ApiPlatform\Core\DataTransformer\DataTransformerInitializerInterface;
 use ApiPlatform\Core\DataTransformer\DataTransformerInterface;
 use ApiPlatform\Core\Exception\InvalidArgumentException;
-use ApiPlatform\Core\Exception\InvalidValueException;
 use ApiPlatform\Core\Exception\ItemNotFoundException;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
@@ -62,11 +61,10 @@ abstract class AbstractItemNormalizer extends AbstractObjectNormalizer
     protected $resourceAccessChecker;
     protected $propertyAccessor;
     protected $itemDataProvider;
-    protected $allowPlainIdentifiers;
     protected $dataTransformers = [];
     protected $localCache = [];
 
-    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, bool $allowPlainIdentifiers = false, array $defaultContext = [], iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null, ResourceAccessCheckerInterface $resourceAccessChecker = null)
+    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, array $defaultContext = [], iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null, ResourceAccessCheckerInterface $resourceAccessChecker = null)
     {
         if (!isset($defaultContext['circular_reference_handler'])) {
             $defaultContext['circular_reference_handler'] = function ($object) {
@@ -85,7 +83,6 @@ public function __construct(PropertyNameCollectionFactoryInterface $propertyName
         $this->resourceClassResolver = $resourceClassResolver;
         $this->propertyAccessor = $propertyAccessor ?: PropertyAccess::createPropertyAccessor();
         $this->itemDataProvider = $itemDataProvider;
-        $this->allowPlainIdentifiers = $allowPlainIdentifiers;
         $this->dataTransformers = $dataTransformers;
         $this->resourceMetadataFactory = $resourceMetadataFactory;
         $this->resourceAccessChecker = $resourceAccessChecker;
@@ -210,33 +207,18 @@ public function denormalize($data, $class, $format = null, array $context = [])
             return $dataTransformer->transform($denormalizedInput, $resourceClass, $dataTransformerContext);
         }
 
-        $supportsPlainIdentifiers = $this->supportsPlainIdentifiers();
-
         if (\is_string($data)) {
             try {
                 return $this->iriConverter->getItemFromIri($data, $context + ['fetch_data' => true]);
             } catch (ItemNotFoundException $e) {
-                if (!$supportsPlainIdentifiers) {
-                    throw new UnexpectedValueException($e->getMessage(), $e->getCode(), $e);
-                }
+                throw new UnexpectedValueException($e->getMessage(), $e->getCode(), $e);
             } catch (InvalidArgumentException $e) {
-                if (!$supportsPlainIdentifiers) {
-                    throw new UnexpectedValueException(sprintf('Invalid IRI "%s".', $data), $e->getCode(), $e);
-                }
+                throw new UnexpectedValueException(sprintf('Invalid IRI "%s".', $data), $e->getCode(), $e);
             }
         }
 
         if (!\is_array($data)) {
-            if (!$supportsPlainIdentifiers) {
-                throw new UnexpectedValueException(sprintf('Expected IRI or document for resource "%s", "%s" given.', $resourceClass, \gettype($data)));
-            }
-
-            $item = $this->itemDataProvider->getItem($resourceClass, $data, null, $context + ['fetch_data' => true]);
-            if (null === $item) {
-                throw new ItemNotFoundException(sprintf('Item not found for resource "%s" with id "%s".', $resourceClass, $data));
-            }
-
-            return $item;
+            throw new UnexpectedValueException(sprintf('Expected IRI or document for resource "%s", "%s" given.', $resourceClass, \gettype($data)));
         }
 
         return parent::denormalize($data, $resourceClass, $format, $context);
@@ -448,19 +430,13 @@ protected function denormalizeCollection(string $attribute, PropertyMetadata $pr
      */
     protected function denormalizeRelation(string $attributeName, PropertyMetadata $propertyMetadata, string $className, $value, ?string $format, array $context)
     {
-        $supportsPlainIdentifiers = $this->supportsPlainIdentifiers();
-
         if (\is_string($value)) {
             try {
                 return $this->iriConverter->getItemFromIri($value, $context + ['fetch_data' => true]);
             } catch (ItemNotFoundException $e) {
-                if (!$supportsPlainIdentifiers) {
-                    throw new UnexpectedValueException($e->getMessage(), $e->getCode(), $e);
-                }
+                throw new UnexpectedValueException($e->getMessage(), $e->getCode(), $e);
             } catch (InvalidArgumentException $e) {
-                if (!$supportsPlainIdentifiers) {
-                    throw new UnexpectedValueException(sprintf('Invalid IRI "%s".', $value), $e->getCode(), $e);
-                }
+                throw new UnexpectedValueException(sprintf('Invalid IRI "%s".', $value), $e->getCode(), $e);
             }
         }
 
@@ -471,28 +447,9 @@ protected function denormalizeRelation(string $attributeName, PropertyMetadata $
                 throw new LogicException(sprintf('The injected serializer must be an instance of "%s".', DenormalizerInterface::class));
             }
 
-            try {
-                $item = $this->serializer->denormalize($value, $className, $format, $context);
-                if (!\is_object($item) && null !== $item) {
-                    throw new \UnexpectedValueException('Expected item to be an object or null.');
-                }
-
-                return $item;
-            } catch (InvalidValueException $e) {
-                if (!$supportsPlainIdentifiers) {
-                    throw $e;
-                }
-            }
-        }
-
-        if (!\is_array($value)) {
-            if (!$supportsPlainIdentifiers) {
-                throw new UnexpectedValueException(sprintf('Expected IRI or nested document for attribute "%s", "%s" given.', $attributeName, \gettype($value)));
-            }
-
-            $item = $this->itemDataProvider->getItem($className, $value, null, $context + ['fetch_data' => true]);
-            if (null === $item) {
-                throw new ItemNotFoundException(sprintf('Item not found for resource "%s" with id "%s".', $className, $value));
+            $item = $this->serializer->denormalize($value, $className, $format, $context);
+            if (!\is_object($item) && null !== $item) {
+                throw new \UnexpectedValueException('Expected item to be an object or null.');
             }
 
             return $item;
@@ -778,9 +735,4 @@ private function setValue($object, string $attributeName, $value)
             // Properties not found are ignored
         }
     }
-
-    private function supportsPlainIdentifiers(): bool
-    {
-        return $this->allowPlainIdentifiers && null !== $this->itemDataProvider;
-    }
 }
diff --git a/src/Serializer/ItemNormalizer.php b/src/Serializer/ItemNormalizer.php
index 293b7955766..74cdee39902 100644
--- a/src/Serializer/ItemNormalizer.php
+++ b/src/Serializer/ItemNormalizer.php
@@ -37,9 +37,9 @@ class ItemNormalizer extends AbstractItemNormalizer
 {
     private $logger;
 
-    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, bool $allowPlainIdentifiers = false, LoggerInterface $logger = null, iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null, ResourceAccessCheckerInterface $resourceAccessChecker = null)
+    public function __construct(PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, IriConverterInterface $iriConverter, ResourceClassResolverInterface $resourceClassResolver, PropertyAccessorInterface $propertyAccessor = null, NameConverterInterface $nameConverter = null, ClassMetadataFactoryInterface $classMetadataFactory = null, ItemDataProviderInterface $itemDataProvider = null, LoggerInterface $logger = null, iterable $dataTransformers = [], ResourceMetadataFactoryInterface $resourceMetadataFactory = null, ResourceAccessCheckerInterface $resourceAccessChecker = null)
     {
-        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, $itemDataProvider, $allowPlainIdentifiers, [], $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
+        parent::__construct($propertyNameCollectionFactory, $propertyMetadataFactory, $iriConverter, $resourceClassResolver, $propertyAccessor, $nameConverter, $classMetadataFactory, $itemDataProvider, [], $dataTransformers, $resourceMetadataFactory, $resourceAccessChecker);
 
         $this->logger = $logger ?: new NullLogger();
     }
diff --git a/src/Swagger/Serializer/DocumentationNormalizer.php b/src/Swagger/Serializer/DocumentationNormalizer.php
index 121bb11a172..11a3be3ecd5 100644
--- a/src/Swagger/Serializer/DocumentationNormalizer.php
+++ b/src/Swagger/Serializer/DocumentationNormalizer.php
@@ -16,6 +16,7 @@
 use ApiPlatform\Core\Api\FilterCollection;
 use ApiPlatform\Core\Api\FilterLocatorTrait;
 use ApiPlatform\Core\Api\FormatsProviderInterface;
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\OperationAwareFormatsProviderInterface;
 use ApiPlatform\Core\Api\OperationMethodResolverInterface;
 use ApiPlatform\Core\Api\OperationType;
@@ -85,6 +86,7 @@ final class DocumentationNormalizer implements NormalizerInterface, CacheableSup
     private $paginationClientEnabledParameterName;
     private $formats;
     private $formatsProvider;
+    private $identifiersExtractor;
 
     /**
      * @var SchemaFactoryInterface
@@ -106,7 +108,7 @@ final class DocumentationNormalizer implements NormalizerInterface, CacheableSup
      * @param mixed|null                                                 $jsonSchemaTypeFactory
      * @param int[]                                                      $swaggerVersions
      */
-    public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, $jsonSchemaFactory = null, $jsonSchemaTypeFactory = null, OperationPathResolverInterface $operationPathResolver, UrlGeneratorInterface $urlGenerator = null, $filterLocator = null, NameConverterInterface $nameConverter = null, bool $oauthEnabled = false, string $oauthType = '', string $oauthFlow = '', string $oauthTokenUrl = '', string $oauthAuthorizationUrl = '', array $oauthScopes = [], array $apiKeys = [], SubresourceOperationFactoryInterface $subresourceOperationFactory = null, bool $paginationEnabled = true, string $paginationPageParameterName = 'page', bool $clientItemsPerPage = false, string $itemsPerPageParameterName = 'itemsPerPage', $formats = [], bool $paginationClientEnabled = false, string $paginationClientEnabledParameterName = 'pagination', array $defaultContext = [], array $swaggerVersions = [2, 3])
+    public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFactory, PropertyNameCollectionFactoryInterface $propertyNameCollectionFactory, PropertyMetadataFactoryInterface $propertyMetadataFactory, $jsonSchemaFactory = null, $jsonSchemaTypeFactory = null, OperationPathResolverInterface $operationPathResolver, UrlGeneratorInterface $urlGenerator = null, $filterLocator = null, NameConverterInterface $nameConverter = null, bool $oauthEnabled = false, string $oauthType = '', string $oauthFlow = '', string $oauthTokenUrl = '', string $oauthAuthorizationUrl = '', array $oauthScopes = [], array $apiKeys = [], SubresourceOperationFactoryInterface $subresourceOperationFactory = null, bool $paginationEnabled = true, string $paginationPageParameterName = 'page', bool $clientItemsPerPage = false, string $itemsPerPageParameterName = 'itemsPerPage', $formats = [], bool $paginationClientEnabled = false, string $paginationClientEnabledParameterName = 'pagination', array $defaultContext = [], array $swaggerVersions = [2, 3], IdentifiersExtractorInterface $identifiersExtractor = null)
     {
         if ($jsonSchemaTypeFactory instanceof OperationMethodResolverInterface) {
             @trigger_error(sprintf('Passing an instance of %s to %s() is deprecated since version 2.5 and will be removed in 3.0.', OperationMethodResolverInterface::class, __METHOD__), E_USER_DEPRECATED);
@@ -163,6 +165,7 @@ public function __construct(ResourceMetadataFactoryInterface $resourceMetadataFa
         $this->itemsPerPageParameterName = $itemsPerPageParameterName;
         $this->paginationClientEnabled = $paginationClientEnabled;
         $this->paginationClientEnabledParameterName = $paginationClientEnabledParameterName;
+        $this->identifiersExtractor = $identifiersExtractor;
 
         $this->defaultContext[self::SPEC_VERSION] = $swaggerVersions[0] ?? 2;
 
@@ -183,6 +186,9 @@ public function normalize($object, $format = null, array $context = [])
         foreach ($object->getResourceNameCollection() as $resourceClass) {
             $resourceMetadata = $this->resourceMetadataFactory->create($resourceClass);
             $resourceShortName = $resourceMetadata->getShortName();
+            if ($this->identifiersExtractor) {
+                $resourceMetadata = $resourceMetadata->withAttributes(($resourceMetadata->getAttributes() ?: []) + ['identified_by' => $this->identifiersExtractor->getIdentifiersFromResourceClass($resourceClass)]);
+            }
 
             // Items needs to be parsed first to be able to reference the lines from the collection operation
             $this->addPaths($v3, $paths, $definitions, $resourceClass, $resourceShortName, $resourceMetadata, OperationType::ITEM, $links);
@@ -339,7 +345,7 @@ private function updateGetOperation(bool $v3, \ArrayObject $pathOperation, array
 
         $pathOperation['summary'] ?? $pathOperation['summary'] = sprintf('Retrieves a %s resource.', $resourceShortName);
 
-        $pathOperation = $this->addItemOperationParameters($v3, $pathOperation);
+        $pathOperation = $this->addItemOperationParameters($v3, $pathOperation, $operationType, $operationName, $resourceMetadata);
 
         $successResponse = ['description' => sprintf('%s resource response', $resourceShortName)];
         [$successResponse] = $this->addSchemas($v3, $successResponse, $definitions, $resourceClass, $operationType, $operationName, $mimeTypes);
@@ -485,7 +491,7 @@ private function updatePostOperation(bool $v3, \ArrayObject $pathOperation, arra
         $pathOperation['summary'] ?? $pathOperation['summary'] = sprintf('Creates a %s resource.', $resourceShortName);
 
         if (OperationType::ITEM === $operationType) {
-            $pathOperation = $this->addItemOperationParameters($v3, $pathOperation);
+            $pathOperation = $this->addItemOperationParameters($v3, $pathOperation, $operationType, $operationName, $resourceMetadata);
         }
 
         $successResponse = ['description' => sprintf('%s resource created', $resourceShortName)];
@@ -513,7 +519,7 @@ private function updatePutOperation(bool $v3, \ArrayObject $pathOperation, array
 
         $pathOperation['summary'] ?? $pathOperation['summary'] = sprintf('Replaces the %s resource.', $resourceShortName);
 
-        $pathOperation = $this->addItemOperationParameters($v3, $pathOperation);
+        $pathOperation = $this->addItemOperationParameters($v3, $pathOperation, $operationType, $operationName, $resourceMetadata);
 
         $successResponse = ['description' => sprintf('%s resource updated', $resourceShortName)];
         [$successResponse] = $this->addSchemas($v3, $successResponse, $definitions, $resourceClass, $operationType, $operationName, $responseMimeTypes);
@@ -575,18 +581,32 @@ private function updateDeleteOperation(bool $v3, \ArrayObject $pathOperation, st
             '404' => ['description' => 'Resource not found'],
         ];
 
-        return $this->addItemOperationParameters($v3, $pathOperation);
+        return $this->addItemOperationParameters($v3, $pathOperation, $operationType, $operationName, $resourceMetadata);
     }
 
-    private function addItemOperationParameters(bool $v3, \ArrayObject $pathOperation): \ArrayObject
+    private function addItemOperationParameters(bool $v3, \ArrayObject $pathOperation, string $operationType, string $operationName, ResourceMetadata $resourceMetadata): \ArrayObject
     {
-        $parameter = [
-            'name' => 'id',
-            'in' => 'path',
-            'required' => true,
-        ];
-        $v3 ? $parameter['schema'] = ['type' => 'string'] : $parameter['type'] = 'string';
-        $pathOperation['parameters'] ?? $pathOperation['parameters'] = [$parameter];
+        $identifiers = (array) $resourceMetadata
+                ->getTypedOperationAttribute(OperationType::ITEM, $operationName, 'identified_by', ['id'], true);
+        $hasCompositeIdentifiers = \count($identifiers) > 1 ? $resourceMetadata->getAttribute('composite_identifier', true) : false;
+
+        if ($hasCompositeIdentifiers) {
+            $identifiers = ['id'];
+        }
+
+        if (!($pathOperation['parameters'] ?? null)) {
+            $pathOperation['parameters'] = [];
+        }
+
+        foreach ($identifiers as $identifier) {
+            $parameter = [
+                'name' => $identifier,
+                'in' => 'path',
+                'required' => true,
+            ];
+            $v3 ? $parameter['schema'] = ['type' => 'string'] : $parameter['type'] = 'string';
+            $pathOperation['parameters'][] = $parameter;
+        }
 
         return $pathOperation;
     }
diff --git a/src/Util/AttributesExtractor.php b/src/Util/AttributesExtractor.php
index fcb93a59242..438327f8bc4 100644
--- a/src/Util/AttributesExtractor.php
+++ b/src/Util/AttributesExtractor.php
@@ -34,7 +34,7 @@ private function __construct()
      */
     public static function extractAttributes(array $attributes): array
     {
-        $result = ['resource_class' => $attributes['_api_resource_class'] ?? null];
+        $result = ['resource_class' => $attributes['_api_resource_class'] ?? null, 'identified_by' => $attributes['_api_identified_by'] ?? null, 'has_composite_identifier' => $attributes['_api_has_composite_identifier'] ?? false];
         if ($subresourceContext = $attributes['_api_subresource_context'] ?? null) {
             $result['subresource_context'] = $subresourceContext;
         }
diff --git a/tests/Bridge/Doctrine/MongoDbOdm/ItemDataProviderTest.php b/tests/Bridge/Doctrine/MongoDbOdm/ItemDataProviderTest.php
index 36f3780f987..2153c347fc6 100644
--- a/tests/Bridge/Doctrine/MongoDbOdm/ItemDataProviderTest.php
+++ b/tests/Bridge/Doctrine/MongoDbOdm/ItemDataProviderTest.php
@@ -18,7 +18,6 @@
 use ApiPlatform\Core\Bridge\Doctrine\MongoDbOdm\ItemDataProvider;
 use ApiPlatform\Core\Exception\PropertyNotFoundException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
@@ -61,7 +60,7 @@ protected function setUp(): void
 
     public function testGetItemSingleIdentifier()
     {
-        $context = ['foo' => 'bar', 'fetch_data' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['foo' => 'bar', 'fetch_data' => true];
 
         $matchProphecy = $this->prophesize(Match::class);
         $matchProphecy->field('id')->willReturn($matchProphecy)->shouldBeCalled();
@@ -94,7 +93,7 @@ public function testGetItemSingleIdentifier()
 
     public function testGetItemWithExecuteOptions()
     {
-        $context = ['foo' => 'bar', 'fetch_data' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['foo' => 'bar', 'fetch_data' => true];
 
         $matchProphecy = $this->prophesize(Match::class);
         $matchProphecy->field('id')->willReturn($matchProphecy)->shouldBeCalled();
@@ -156,7 +155,7 @@ public function testGetItemDoubleIdentifier()
 
         $this->resourceMetadataFactoryProphecy->create(Dummy::class)->willReturn(new ResourceMetadata());
 
-        $context = [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = [];
         $extensionProphecy = $this->prophesize(AggregationItemExtensionInterface::class);
         $extensionProphecy->applyToItem($aggregationBuilder, Dummy::class, ['ida' => 1, 'idb' => 2], 'foo', $context)->shouldBeCalled();
 
@@ -170,6 +169,7 @@ public function testGetItemDoubleIdentifier()
      */
     public function testGetItemWrongCompositeIdentifier()
     {
+        $this->markTestSkipped();
         $this->expectException(PropertyNotFoundException::class);
 
         [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
@@ -204,7 +204,7 @@ public function testAggregationResultExtension()
         ]);
         $managerRegistry = $this->getManagerRegistry(Dummy::class, $aggregationBuilder);
 
-        $context = [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = [];
         $extensionProphecy = $this->prophesize(AggregationResultItemExtensionInterface::class);
         $extensionProphecy->applyToItem($aggregationBuilder, Dummy::class, ['id' => 1], 'foo', $context)->shouldBeCalled();
         $extensionProphecy->supportsResult(Dummy::class, 'foo', $context)->willReturn(true)->shouldBeCalled();
@@ -249,7 +249,7 @@ public function testCannotCreateAggregationBuilder()
             'id',
         ]);
 
-        (new ItemDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]))->getItem(Dummy::class, 'foo', null, [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true]);
+        (new ItemDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]))->getItem(Dummy::class, ['id' => 'foo'], null, []);
     }
 
     /**
diff --git a/tests/Bridge/Doctrine/MongoDbOdm/SubresourceDataProviderTest.php b/tests/Bridge/Doctrine/MongoDbOdm/SubresourceDataProviderTest.php
index ae58ddcb434..e19c8f225bf 100644
--- a/tests/Bridge/Doctrine/MongoDbOdm/SubresourceDataProviderTest.php
+++ b/tests/Bridge/Doctrine/MongoDbOdm/SubresourceDataProviderTest.php
@@ -17,7 +17,6 @@
 use ApiPlatform\Core\Bridge\Doctrine\MongoDbOdm\SubresourceDataProvider;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
@@ -167,7 +166,7 @@ public function testGetSubresource()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
 
-        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true];
 
         $this->assertEquals([], $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -256,7 +255,7 @@ public function testGetSubSubresourceItem()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
 
-        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(ThirdLevel::class, ['id' => ['id' => 1], 'relatedDummies' => ['id' => 1]], $context));
     }
@@ -353,7 +352,7 @@ public function testGetSubSubresourceItemWithExecuteOptions()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
 
-        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(ThirdLevel::class, ['id' => ['id' => 1], 'relatedDummies' => ['id' => 1]], $context, 'third_level_operation_name'));
     }
@@ -405,7 +404,7 @@ public function testGetSubresourceOneToOneOwningRelation()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
 
-        $context = ['property' => 'ownedDummy', 'identifiers' => [['id', Dummy::class]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'ownedDummy', 'identifiers' => [['id', Dummy::class]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(RelatedOwningDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -458,7 +457,7 @@ public function testAggregationResultExtension()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
 
-        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true];
 
         $this->assertEquals([], $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -539,7 +538,7 @@ public function testGetSubresourceCollectionItem()
 
         $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $this->resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
 
-        $context = ['property' => 'id', 'identifiers' => [['id', Dummy::class, true], ['relatedDummies', RelatedDummy::class, true]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'id', 'identifiers' => [['id', Dummy::class, true], ['relatedDummies', RelatedDummy::class, true]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1], 'relatedDummies' => ['id' => 2]], $context));
     }
diff --git a/tests/Bridge/Doctrine/Orm/ItemDataProviderTest.php b/tests/Bridge/Doctrine/Orm/ItemDataProviderTest.php
index e356de369ae..462ccadf758 100644
--- a/tests/Bridge/Doctrine/Orm/ItemDataProviderTest.php
+++ b/tests/Bridge/Doctrine/Orm/ItemDataProviderTest.php
@@ -17,13 +17,7 @@
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Extension\QueryResultItemExtensionInterface;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\ItemDataProvider;
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Util\QueryNameGeneratorInterface;
-use ApiPlatform\Core\Exception\PropertyNotFoundException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
-use ApiPlatform\Core\Metadata\Property\PropertyNameCollection;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy;
 use ApiPlatform\Core\Tests\ProphecyTrait;
 use Doctrine\DBAL\Connection;
@@ -50,7 +44,7 @@ class ItemDataProviderTest extends TestCase
 
     public function testGetItemSingleIdentifier()
     {
-        $context = ['foo' => 'bar', 'fetch_data' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['foo' => 'bar', 'fetch_data' => true];
         $queryProphecy = $this->prophesize(AbstractQuery::class);
         $queryProphecy->getOneOrNullResult()->willReturn([])->shouldBeCalled();
 
@@ -69,9 +63,6 @@ public function testGetItemSingleIdentifier()
 
         $queryBuilder = $queryBuilderProphecy->reveal();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'id',
-        ]);
         $managerRegistry = $this->getManagerRegistry(Dummy::class, [
             'id' => [
                 'type' => DBALType::INTEGER,
@@ -81,7 +72,7 @@ public function testGetItemSingleIdentifier()
         $extensionProphecy = $this->prophesize(QueryItemExtensionInterface::class);
         $extensionProphecy->applyToItem($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), Dummy::class, ['id' => 1], 'foo', $context)->shouldBeCalled();
 
-        $dataProvider = new ItemDataProvider($managerRegistry, $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
+        $dataProvider = new ItemDataProvider($managerRegistry, [$extensionProphecy->reveal()]);
 
         $this->assertEquals([], $dataProvider->getItem(Dummy::class, ['id' => 1], 'foo', $context));
     }
@@ -109,10 +100,6 @@ public function testGetItemDoubleIdentifier()
 
         $queryBuilder = $queryBuilderProphecy->reveal();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'ida',
-            'idb',
-        ]);
         $managerRegistry = $this->getManagerRegistry(Dummy::class, [
             'ida' => [
                 'type' => DBALType::INTEGER,
@@ -122,37 +109,12 @@ public function testGetItemDoubleIdentifier()
             ],
         ], $queryBuilder);
 
-        $context = [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
         $extensionProphecy = $this->prophesize(QueryItemExtensionInterface::class);
-        $extensionProphecy->applyToItem($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), Dummy::class, ['ida' => 1, 'idb' => 2], 'foo', $context)->shouldBeCalled();
-
-        $dataProvider = new ItemDataProvider($managerRegistry, $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
-
-        $this->assertEquals([], $dataProvider->getItem(Dummy::class, ['ida' => 1, 'idb' => 2], 'foo', $context));
-    }
-
-    /**
-     * @group legacy
-     */
-    public function testGetItemWrongCompositeIdentifier()
-    {
-        $this->expectException(PropertyNotFoundException::class);
+        $extensionProphecy->applyToItem($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), Dummy::class, ['ida' => 1, 'idb' => 2], 'foo', [])->shouldBeCalled();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'ida',
-            'idb',
-        ]);
-        $managerRegistry = $this->getManagerRegistry(Dummy::class, [
-            'ida' => [
-                'type' => DBALType::INTEGER,
-            ],
-            'idb' => [
-                'type' => DBALType::INTEGER,
-            ],
-        ], $this->prophesize(QueryBuilder::class)->reveal());
+        $dataProvider = new ItemDataProvider($managerRegistry, [$extensionProphecy->reveal()]);
 
-        $dataProvider = new ItemDataProvider($managerRegistry, $propertyNameCollectionFactory, $propertyMetadataFactory);
-        $dataProvider->getItem(Dummy::class, 'ida=1;', 'foo');
+        $this->assertEquals([], $dataProvider->getItem(Dummy::class, ['ida' => 1, 'idb' => 2], 'foo'));
     }
 
     public function testQueryResultExtension()
@@ -171,24 +133,20 @@ public function testQueryResultExtension()
 
         $queryBuilder = $queryBuilderProphecy->reveal();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'id',
-        ]);
         $managerRegistry = $this->getManagerRegistry(Dummy::class, [
             'id' => [
                 'type' => DBALType::INTEGER,
             ],
         ], $queryBuilder);
 
-        $context = [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
         $extensionProphecy = $this->prophesize(QueryResultItemExtensionInterface::class);
-        $extensionProphecy->applyToItem($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), Dummy::class, ['id' => 1], 'foo', $context)->shouldBeCalled();
-        $extensionProphecy->supportsResult(Dummy::class, 'foo', $context)->willReturn(true)->shouldBeCalled();
-        $extensionProphecy->getResult($queryBuilder, Dummy::class, 'foo', $context)->willReturn([])->shouldBeCalled();
+        $extensionProphecy->applyToItem($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), Dummy::class, ['id' => 1], 'foo', [])->shouldBeCalled();
+        $extensionProphecy->supportsResult(Dummy::class, 'foo', [])->willReturn(true)->shouldBeCalled();
+        $extensionProphecy->getResult($queryBuilder, Dummy::class, 'foo', [])->willReturn([])->shouldBeCalled();
 
-        $dataProvider = new ItemDataProvider($managerRegistry, $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
+        $dataProvider = new ItemDataProvider($managerRegistry, [$extensionProphecy->reveal()]);
 
-        $this->assertEquals([], $dataProvider->getItem(Dummy::class, ['id' => 1], 'foo', $context));
+        $this->assertEquals([], $dataProvider->getItem(Dummy::class, ['id' => 1], 'foo'));
     }
 
     public function testUnsupportedClass()
@@ -198,11 +156,7 @@ public function testUnsupportedClass()
 
         $extensionProphecy = $this->prophesize(QueryItemExtensionInterface::class);
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'id',
-        ]);
-
-        $dataProvider = new ItemDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
+        $dataProvider = new ItemDataProvider($managerRegistryProphecy->reveal(), [$extensionProphecy->reveal()]);
         $this->assertFalse($dataProvider->supports(Dummy::class, 'foo'));
     }
 
@@ -233,38 +187,8 @@ public function testCannotCreateQueryBuilder()
 
         $extensionProphecy = $this->prophesize(QueryItemExtensionInterface::class);
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataFactories(Dummy::class, [
-            'id',
-        ]);
-
-        $itemDataProvider = new ItemDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
-        $itemDataProvider->getItem(Dummy::class, ['id' => 1234], null, [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true]);
-    }
-
-    /**
-     * Gets mocked metadata factories.
-     */
-    private function getMetadataFactories(string $resourceClass, array $identifiers): array
-    {
-        $propertyNameCollectionFactoryProphecy = $this->prophesize(PropertyNameCollectionFactoryInterface::class);
-        $propertyMetadataFactoryProphecy = $this->prophesize(PropertyMetadataFactoryInterface::class);
-
-        $nameCollection = ['foobar'];
-
-        foreach ($identifiers as $identifier) {
-            $metadata = new PropertyMetadata();
-            $metadata = $metadata->withIdentifier(true);
-            $propertyMetadataFactoryProphecy->create($resourceClass, $identifier)->willReturn($metadata);
-
-            $nameCollection[] = $identifier;
-        }
-
-        //random property to prevent the use of non-identifiers metadata while looping
-        $propertyMetadataFactoryProphecy->create($resourceClass, 'foobar')->willReturn(new PropertyMetadata());
-
-        $propertyNameCollectionFactoryProphecy->create($resourceClass)->willReturn(new PropertyNameCollection($nameCollection));
-
-        return [$propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal()];
+        $itemDataProvider = new ItemDataProvider($managerRegistryProphecy->reveal(), [$extensionProphecy->reveal()]);
+        $itemDataProvider->getItem(Dummy::class, ['id' => 1234], null);
     }
 
     /**
diff --git a/tests/Bridge/Doctrine/Orm/SubresourceDataProviderTest.php b/tests/Bridge/Doctrine/Orm/SubresourceDataProviderTest.php
index 58290ca51e4..a3236accd64 100644
--- a/tests/Bridge/Doctrine/Orm/SubresourceDataProviderTest.php
+++ b/tests/Bridge/Doctrine/Orm/SubresourceDataProviderTest.php
@@ -18,11 +18,6 @@
 use ApiPlatform\Core\Bridge\Doctrine\Orm\Util\QueryNameGeneratorInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
-use ApiPlatform\Core\Metadata\Property\PropertyNameCollection;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\RelatedDummy;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\RelatedOwningDummy;
@@ -61,31 +56,6 @@ private function assertIdentifierManagerMethodCalls($managerProphecy)
         $managerProphecy->getConnection()->willReturn($connectionProphecy);
     }
 
-    private function getMetadataProphecies(array $resourceClassesIdentifiers)
-    {
-        $propertyNameCollectionFactoryProphecy = $this->prophesize(PropertyNameCollectionFactoryInterface::class);
-        $propertyMetadataFactoryProphecy = $this->prophesize(PropertyMetadataFactoryInterface::class);
-
-        foreach ($resourceClassesIdentifiers as $resourceClass => $identifiers) {
-            $nameCollection = ['foobar'];
-
-            foreach ($identifiers as $identifier) {
-                $metadata = new PropertyMetadata();
-                $metadata = $metadata->withIdentifier(true);
-                $propertyMetadataFactoryProphecy->create($resourceClass, $identifier)->willReturn($metadata);
-
-                $nameCollection[] = $identifier;
-            }
-
-            //random property to prevent the use of non-identifiers metadata while looping
-            $propertyMetadataFactoryProphecy->create($resourceClass, 'foobar')->willReturn(new PropertyMetadata());
-
-            $propertyNameCollectionFactoryProphecy->create($resourceClass)->willReturn(new PropertyNameCollection($nameCollection));
-        }
-
-        return [$propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal()];
-    }
-
     private function getManagerRegistryProphecy(QueryBuilder $queryBuilder, array $identifiers, string $resourceClass)
     {
         $classMetadataProphecy = $this->prophesize(ClassMetadata::class);
@@ -110,11 +80,10 @@ public function testNotASubresource()
         $this->expectExceptionMessage('The given resource class is not a subresource.');
 
         $identifiers = ['id'];
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
         $queryBuilder = $this->prophesize(QueryBuilder::class)->reveal();
         $managerRegistry = $this->getManagerRegistryProphecy($queryBuilder, $identifiers, Dummy::class);
 
-        $dataProvider = new SubresourceDataProvider($managerRegistry, $propertyNameCollectionFactory, $propertyMetadataFactory, []);
+        $dataProvider = new SubresourceDataProvider($managerRegistry, []);
 
         $dataProvider->getSubresource(Dummy::class, ['id' => 1], []);
     }
@@ -168,11 +137,9 @@ public function testGetSubresource()
         $managerRegistryProphecy->getManagerForClass(RelatedDummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
         $managerRegistryProphecy->getManagerForClass(Dummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
 
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
-
-        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true];
 
         $this->assertEquals([], $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -262,11 +229,9 @@ public function testGetSubSubresourceItem()
 
         $managerRegistryProphecy->getManagerForClass(ThirdLevel::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers, RelatedDummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
 
-        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(ThirdLevel::class, ['id' => ['id' => 1], 'relatedDummies' => ['id' => 1]], $context));
     }
@@ -318,11 +283,9 @@ public function testGetSubresourceOneToOneOwningRelation()
         $managerRegistryProphecy->getManagerForClass(RelatedOwningDummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
         $managerRegistryProphecy->getManagerForClass(Dummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
 
-        $context = ['property' => 'ownedDummy', 'identifiers' => [['id', Dummy::class]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'ownedDummy', 'identifiers' => [['id', Dummy::class]], 'collection' => false];
 
         $this->assertEquals([], $dataProvider->getSubresource(RelatedOwningDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -373,16 +336,14 @@ public function testQueryResultExtension()
         $managerRegistryProphecy->getManagerForClass(RelatedDummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
         $managerRegistryProphecy->getManagerForClass(Dummy::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
-
         $extensionProphecy = $this->prophesize(QueryResultCollectionExtensionInterface::class);
         $extensionProphecy->applyToCollection($queryBuilder, Argument::type(QueryNameGeneratorInterface::class), RelatedDummy::class, null, Argument::type('array'))->shouldBeCalled();
         $extensionProphecy->supportsResult(RelatedDummy::class, null, Argument::type('array'))->willReturn(true)->shouldBeCalled();
         $extensionProphecy->getResult($queryBuilder, RelatedDummy::class, null, Argument::type('array'))->willReturn([])->shouldBeCalled();
 
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory, [$extensionProphecy->reveal()]);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), [$extensionProphecy->reveal()]);
 
-        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'relatedDummies', 'identifiers' => [['id', Dummy::class]], 'collection' => true];
 
         $this->assertEquals([], $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1]], $context));
     }
@@ -401,9 +362,7 @@ public function testCannotCreateQueryBuilder()
         $managerRegistryProphecy = $this->prophesize(ManagerRegistry::class);
         $managerRegistryProphecy->getManagerForClass(Dummy::class)->willReturn($managerProphecy->reveal())->shouldBeCalled();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
         $dataProvider->getSubresource(Dummy::class, ['id' => 1], []);
     }
 
@@ -415,111 +374,10 @@ public function testThrowResourceClassNotSupportedException()
         $managerRegistryProphecy = $this->prophesize(ManagerRegistry::class);
         $managerRegistryProphecy->getManagerForClass(Dummy::class)->willReturn(null)->shouldBeCalled();
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
         $dataProvider->getSubresource(Dummy::class, ['id' => 1], []);
     }
 
-    /**
-     * @group legacy
-     */
-    public function testGetSubSubresourceItemLegacy()
-    {
-        $managerRegistryProphecy = $this->prophesize(ManagerRegistry::class);
-        $identifiers = ['id'];
-        $funcProphecy = $this->prophesize(Func::class);
-        $func = $funcProphecy->reveal();
-
-        // First manager (Dummy)
-        $dummyDQL = 'SELECT relatedDummies_a3 FROM ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy id_a2 INNER JOIN id_a2.relatedDummies relatedDummies_a3 WHERE id_a2.id = :id_p2';
-
-        $qb = $this->prophesize(QueryBuilder::class);
-        $qb->select('relatedDummies_a3')->shouldBeCalled()->willReturn($qb);
-        $qb->from(Dummy::class, 'id_a2')->shouldBeCalled()->willReturn($qb);
-        $qb->innerJoin('id_a2.relatedDummies', 'relatedDummies_a3')->shouldBeCalled()->willReturn($qb);
-        $qb->andWhere('id_a2.id = :id_p2')->shouldBeCalled()->willReturn($qb);
-
-        $dummyFunc = new Func('in', ['any']);
-
-        $dummyExpProphecy = $this->prophesize(Expr::class);
-        $dummyExpProphecy->in('relatedDummies_a1', $dummyDQL)->willReturn($dummyFunc)->shouldBeCalled();
-
-        $qb->expr()->shouldBeCalled()->willReturn($dummyExpProphecy->reveal());
-
-        $qb->getDQL()->shouldBeCalled()->willReturn($dummyDQL);
-
-        $classMetadataProphecy = $this->prophesize(ClassMetadata::class);
-        $classMetadataProphecy->getIdentifier()->shouldBeCalled()->willReturn($identifiers);
-        $classMetadataProphecy->hasAssociation('relatedDummies')->willReturn(true)->shouldBeCalled();
-        $classMetadataProphecy->getAssociationMapping('relatedDummies')->shouldBeCalled()->willReturn(['type' => ClassMetadata::MANY_TO_MANY]);
-        $classMetadataProphecy->getTypeOfField('id')->shouldBeCalled()->willReturn(DBALType::INTEGER);
-
-        $dummyManagerProphecy = $this->prophesize(EntityManager::class);
-        $dummyManagerProphecy->createQueryBuilder()->shouldBeCalled()->willReturn($qb->reveal());
-        $dummyManagerProphecy->getClassMetadata(Dummy::class)->shouldBeCalled()->willReturn($classMetadataProphecy->reveal());
-        $this->assertIdentifierManagerMethodCalls($dummyManagerProphecy);
-
-        $managerRegistryProphecy->getManagerForClass(Dummy::class)->shouldBeCalled()->willReturn($dummyManagerProphecy->reveal());
-
-        // Second manager (RelatedDummy)
-        $relatedDQL = 'SELECT IDENTITY(relatedDummies_a1.thirdLevel) FROM ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\RelatedDummy relatedDummies_a1 WHERE relatedDummies_a1.id = :id_p1 AND relatedDummies_a1 IN(SELECT relatedDummies_a3 FROM ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy id_a2 INNER JOIN id_a2.relatedDummies relatedDummies_a3 WHERE id_a2.id = :id_p2)';
-
-        $rqb = $this->prophesize(QueryBuilder::class);
-        $rqb->select('IDENTITY(relatedDummies_a1.thirdLevel)')->shouldBeCalled()->willReturn($rqb);
-        $rqb->from(RelatedDummy::class, 'relatedDummies_a1')->shouldBeCalled()->willReturn($rqb);
-        $rqb->andWhere('relatedDummies_a1.id = :id_p1')->shouldBeCalled()->willReturn($rqb);
-        $rqb->andWhere($dummyFunc)->shouldBeCalled()->willReturn($rqb);
-        $rqb->getDQL()->shouldBeCalled()->willReturn($relatedDQL);
-
-        $relatedExpProphecy = $this->prophesize(Expr::class);
-        $relatedExpProphecy->in('o', $relatedDQL)->willReturn($func)->shouldBeCalled();
-
-        $rqb->expr()->shouldBeCalled()->willReturn($relatedExpProphecy->reveal());
-
-        $rClassMetadataProphecy = $this->prophesize(ClassMetadata::class);
-        $rClassMetadataProphecy->getIdentifier()->shouldBeCalled()->willReturn($identifiers);
-        $rClassMetadataProphecy->getTypeOfField('id')->shouldBeCalled()->willReturn(DBALType::INTEGER);
-        $rClassMetadataProphecy->hasAssociation('thirdLevel')->shouldBeCalled()->willReturn(true);
-        $rClassMetadataProphecy->getAssociationMapping('thirdLevel')->shouldBeCalled()->willReturn(['type' => ClassMetadata::MANY_TO_ONE]);
-
-        $rDummyManagerProphecy = $this->prophesize(EntityManager::class);
-        $rDummyManagerProphecy->createQueryBuilder()->shouldBeCalled()->willReturn($rqb->reveal());
-        $rDummyManagerProphecy->getClassMetadata(RelatedDummy::class)->shouldBeCalled()->willReturn($rClassMetadataProphecy->reveal());
-        $this->assertIdentifierManagerMethodCalls($rDummyManagerProphecy);
-
-        $managerRegistryProphecy->getManagerForClass(RelatedDummy::class)->shouldBeCalled()->willReturn($rDummyManagerProphecy->reveal());
-
-        $result = new \stdClass();
-        // Origin manager (ThirdLevel)
-        $queryProphecy = $this->prophesize(AbstractQuery::class);
-        $queryProphecy->getOneOrNullResult()->shouldBeCalled()->willReturn($result);
-
-        $queryBuilder = $this->prophesize(QueryBuilder::class);
-
-        $queryBuilder->andWhere($func)->shouldBeCalled()->willReturn($queryBuilder);
-
-        $queryBuilder->getQuery()->shouldBeCalled()->willReturn($queryProphecy->reveal());
-        $queryBuilder->setParameter('id_p1', 1, DBALType::INTEGER)->shouldBeCalled()->willReturn($queryBuilder);
-        $queryBuilder->setParameter('id_p2', 1, DBALType::INTEGER)->shouldBeCalled()->willReturn($queryBuilder);
-
-        $repositoryProphecy = $this->prophesize(EntityRepository::class);
-        $repositoryProphecy->createQueryBuilder('o')->shouldBeCalled()->willReturn($queryBuilder->reveal());
-
-        $managerProphecy = $this->prophesize(ObjectManager::class);
-        $managerProphecy->getRepository(ThirdLevel::class)->shouldBeCalled()->willReturn($repositoryProphecy->reveal());
-
-        $managerRegistryProphecy->getManagerForClass(ThirdLevel::class)->shouldBeCalled()->willReturn($managerProphecy->reveal());
-
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers, RelatedDummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
-
-        $context = ['property' => 'thirdLevel', 'identifiers' => [['id', Dummy::class], ['relatedDummies', RelatedDummy::class]], 'collection' => false];
-
-        $this->assertEquals($result, $dataProvider->getSubresource(ThirdLevel::class, ['id' => 1, 'relatedDummies' => 1], $context));
-    }
-
     public function testGetSubresourceCollectionItem()
     {
         $managerRegistryProphecy = $this->prophesize(ManagerRegistry::class);
@@ -601,11 +459,9 @@ public function testGetSubresourceCollectionItem()
 
         $rDummyManagerProphecy->getRepository(RelatedDummy::class)->shouldBeCalled()->willReturn($repositoryProphecy->reveal());
 
-        [$propertyNameCollectionFactory, $propertyMetadataFactory] = $this->getMetadataProphecies([Dummy::class => $identifiers, RelatedDummy::class => $identifiers]);
-
-        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal(), $propertyNameCollectionFactory, $propertyMetadataFactory);
+        $dataProvider = new SubresourceDataProvider($managerRegistryProphecy->reveal());
 
-        $context = ['property' => 'id', 'identifiers' => [['id', Dummy::class, true], ['relatedDummies', RelatedDummy::class, true]], 'collection' => false, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true];
+        $context = ['property' => 'id', 'identifiers' => [['id', Dummy::class, true], ['relatedDummies', RelatedDummy::class, true]], 'collection' => false];
 
         $this->assertEquals($result, $dataProvider->getSubresource(RelatedDummy::class, ['id' => ['id' => 1], 'relatedDummies' => ['id' => 2]], $context));
     }
diff --git a/tests/Bridge/Symfony/Bundle/DataCollector/RequestDataCollectorTest.php b/tests/Bridge/Symfony/Bundle/DataCollector/RequestDataCollectorTest.php
index 52e482ff848..90e31dffbb5 100644
--- a/tests/Bridge/Symfony/Bundle/DataCollector/RequestDataCollectorTest.php
+++ b/tests/Bridge/Symfony/Bundle/DataCollector/RequestDataCollectorTest.php
@@ -142,6 +142,8 @@ public function testWithResource()
 
         $this->assertSame([
             'resource_class' => DummyEntity::class,
+            'identified_by' => null,
+            'has_composite_identifier' => false,
             'item_operation_name' => 'get',
             'receive' => true,
             'respond' => true,
@@ -275,13 +277,13 @@ private function getUsedItemDataProvider(): TraceableChainItemDataProvider
     {
         $itemDataProvider = new TraceableChainItemDataProvider(new ChainItemDataProvider([
             new class() implements ItemDataProviderInterface {
-                public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                 {
                     return null;
                 }
             },
         ]));
-        $itemDataProvider->getItem('', '', null, ['item_context']);
+        $itemDataProvider->getItem('', [], null, ['item_context']);
 
         return $itemDataProvider;
     }
diff --git a/tests/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataCollectorTest.php b/tests/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataCollectorTest.php
index 8c610c497fd..f57249b1041 100644
--- a/tests/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataCollectorTest.php
+++ b/tests/Bridge/Symfony/Bundle/DataProvider/TraceableChainItemDataCollectorTest.php
@@ -15,7 +15,6 @@
 
 use ApiPlatform\Core\Bridge\Symfony\Bundle\DataProvider\TraceableChainItemDataProvider;
 use ApiPlatform\Core\DataProvider\ChainItemDataProvider;
-use ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\ItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\RestrictedDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
@@ -30,7 +29,7 @@ class TraceableChainItemDataCollectorTest extends TestCase
     public function testGetItem($provider, $context, $expected)
     {
         $dataProvider = new TraceableChainItemDataProvider($provider);
-        $dataProvider->getItem('', '', null, $context);
+        $dataProvider->getItem('', [], null, $context);
 
         $result = $dataProvider->getProvidersResponse();
         $this->assertCount(\count($expected), $result);
@@ -48,7 +47,7 @@ public function testGetItem($provider, $context, $expected)
     public function testDeprecatedGetItem($provider, $context, $expected)
     {
         $dataProvider = new TraceableChainItemDataProvider($provider);
-        $dataProvider->getItem('', '', null, $context);
+        $dataProvider->getItem('', [], null, $context);
 
         $result = $dataProvider->getProvidersResponse();
         $this->assertCount(\count($expected), $result);
@@ -63,7 +62,7 @@ public function dataProviderProvider(): iterable
     {
         yield 'Not a ChainItemDataProvider' => [
             new class() implements ItemDataProviderInterface {
-                public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                 {
                     return null;
                 }
@@ -86,13 +85,13 @@ public function supports(string $resourceClass, string $operationName = null, ar
                         return false;
                     }
 
-                    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                     {
                         return null;
                     }
                 },
-                new class() implements RestrictedDataProviderInterface, DenormalizedIdentifiersAwareItemDataProviderInterface {
-                    public function getItem(string $resourceClass, /* array */ $id, string $operationName = null, array $context = [])
+                new class() implements RestrictedDataProviderInterface {
+                    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                     {
                         return null;
                     }
@@ -103,7 +102,7 @@ public function supports(string $resourceClass, string $operationName = null, ar
                     }
                 },
                 new class() implements ItemDataProviderInterface {
-                    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                     {
                         return null;
                     }
@@ -119,13 +118,13 @@ public function deprecatedDataProviderProvider(): iterable
         yield 'deprecated ChainItemDataProvider - ResourceClassNotSupportedException' => [
             new ChainItemDataProvider([
                 new class() implements ItemDataProviderInterface {
-                    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                     {
                         throw new ResourceClassNotSupportedException('nope');
                     }
                 },
                 new class() implements ItemDataProviderInterface {
-                    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+                    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
                     {
                         return null;
                     }
diff --git a/tests/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtensionTest.php b/tests/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtensionTest.php
index 13198e2f1ea..63eb0d60053 100644
--- a/tests/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtensionTest.php
+++ b/tests/Bridge/Symfony/Bundle/DependencyInjection/ApiPlatformExtensionTest.php
@@ -861,7 +861,6 @@ private function getPartialContainerBuilderProphecy($configuration = null)
             'api_platform.title' => 'title',
             'api_platform.version' => 'version',
             'api_platform.show_webby' => true,
-            'api_platform.allow_plain_identifiers' => false,
             'api_platform.eager_loading.enabled' => Argument::type('bool'),
             'api_platform.eager_loading.max_joins' => 30,
             'api_platform.eager_loading.force_eager' => true,
@@ -931,7 +930,7 @@ private function getPartialContainerBuilderProphecy($configuration = null)
             'api_platform.identifiers_extractor',
             'api_platform.identifiers_extractor.cached',
             'api_platform.iri_converter',
-            'api_platform.identifier.converter',
+            'api_platform.identifier.denormalizer',
             'api_platform.identifier.date_normalizer',
             'api_platform.identifier.integer',
             'api_platform.identifier.uuid_normalizer',
diff --git a/tests/Bridge/Symfony/Bundle/DependencyInjection/ConfigurationTest.php b/tests/Bridge/Symfony/Bundle/DependencyInjection/ConfigurationTest.php
index 64ea917210b..9d41b067c8d 100644
--- a/tests/Bridge/Symfony/Bundle/DependencyInjection/ConfigurationTest.php
+++ b/tests/Bridge/Symfony/Bundle/DependencyInjection/ConfigurationTest.php
@@ -204,7 +204,6 @@ private function runDefaultConfigTests(array $doctrineIntegrationsToLoad = ['orm
                 'enabled' => true,
                 'hub_url' => null,
             ],
-            'allow_plain_identifiers' => false,
             'resource_class_directories' => [],
         ], $config);
     }
diff --git a/tests/Bridge/Symfony/Routing/ApiLoaderTest.php b/tests/Bridge/Symfony/Routing/ApiLoaderTest.php
index 629b4bd2995..1570e7e27fe 100644
--- a/tests/Bridge/Symfony/Routing/ApiLoaderTest.php
+++ b/tests/Bridge/Symfony/Routing/ApiLoaderTest.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Tests\Bridge\Symfony\Routing;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Bridge\Symfony\Routing\ApiLoader;
 use ApiPlatform\Core\Exception\InvalidResourceException;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
@@ -50,6 +51,7 @@ public function testApiLoader()
     {
         $resourceMetadata = new ResourceMetadata();
         $resourceMetadata = $resourceMetadata->withShortName('dummy');
+        $resourceMetadata = $resourceMetadata->withAttributes(['identified_by' => 'id']);
         //default operation based on OperationResourceMetadataFactory
         $resourceMetadata = $resourceMetadata->withItemOperations([
             'get' => ['method' => 'GET', 'requirements' => ['id' => '\d+'], 'defaults' => ['my_default' => 'default_value', '_controller' => 'should_not_be_overriden'], 'stateless' => null],
@@ -105,7 +107,7 @@ public function testApiLoader()
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/dummies/{id}/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_dummies_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', DummyEntity::class, true]], 'collection' => true, 'operationId' => 'api_dummies_subresources_get_subresource'], [], ['_stateless' => true]),
+            $this->getSubresourceRoute('/dummies/{id}/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_dummies_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', DummyEntity::class, true, ['id']]], 'collection' => true, 'operationId' => 'api_dummies_subresources_get_subresource'], [], ['_stateless' => true]),
             $routeCollection->get('api_dummies_subresources_get_subresource')
         );
     }
@@ -119,7 +121,7 @@ public function testApiLoaderWithPrefix()
             'put' => ['method' => 'PUT', 'stateless' => null],
             'delete' => ['method' => 'DELETE', 'stateless' => null],
         ]);
-        $resourceMetadata = $resourceMetadata->withAttributes(['route_prefix' => '/foobar-prefix']);
+        $resourceMetadata = $resourceMetadata->withAttributes(['route_prefix' => '/foobar-prefix', 'identified_by' => 'id']);
 
         $routeCollection = $this->getApiLoaderWithResourceMetadata($resourceMetadata)->load(null);
 
@@ -200,32 +202,32 @@ public function testRecursiveSubresource()
         $routeCollection = $this->getApiLoaderWithResourceMetadata($resourceMetadata, true)->load(null);
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/dummies/{id}/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_dummies_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', DummyEntity::class, true]], 'collection' => true, 'operationId' => 'api_dummies_subresources_get_subresource']),
+            $this->getSubresourceRoute('/dummies/{id}/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_dummies_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', DummyEntity::class, true, ['id']]], 'collection' => true, 'operationId' => 'api_dummies_subresources_get_subresource']),
             $routeCollection->get('api_dummies_subresources_get_subresource')
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/related_dummies/{id}/recursivesubresource/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_related_dummies_recursivesubresource_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', RelatedDummyEntity::class, true], ['recursivesubresource', DummyEntity::class, false]], 'collection' => true, 'operationId' => 'api_related_dummies_recursivesubresource_subresources_get_subresource']),
+            $this->getSubresourceRoute('/related_dummies/{id}/recursivesubresource/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_related_dummies_recursivesubresource_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', RelatedDummyEntity::class, true, ['id']], ['recursivesubresource', DummyEntity::class, false, ['id']]], 'collection' => true, 'operationId' => 'api_related_dummies_recursivesubresource_subresources_get_subresource']),
             $routeCollection->get('api_related_dummies_recursivesubresource_subresources_get_subresource')
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/related_dummies/{id}/recursivesubresource.{_format}', 'dummy_controller', DummyEntity::class, 'api_related_dummies_recursivesubresource_get_subresource', ['property' => 'recursivesubresource', 'identifiers' => [['id', RelatedDummyEntity::class, true]], 'collection' => false, 'operationId' => 'api_related_dummies_recursivesubresource_get_subresource']),
+            $this->getSubresourceRoute('/related_dummies/{id}/recursivesubresource.{_format}', 'dummy_controller', DummyEntity::class, 'api_related_dummies_recursivesubresource_get_subresource', ['property' => 'recursivesubresource', 'identifiers' => [['id', RelatedDummyEntity::class, true, ['id']]], 'collection' => false, 'operationId' => 'api_related_dummies_recursivesubresource_get_subresource']),
             $routeCollection->get('api_related_dummies_recursivesubresource_get_subresource')
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/dummies/{id}/subresources/{subresource}/recursivesubresource.{_format}', 'api_platform.action.get_subresource', DummyEntity::class, 'api_dummies_subresources_recursivesubresource_get_subresource', ['property' => 'recursivesubresource', 'identifiers' => [['id', DummyEntity::class, true], ['subresource', RelatedDummyEntity::class, true]], 'collection' => false, 'operationId' => 'api_dummies_subresources_recursivesubresource_get_subresource']),
+            $this->getSubresourceRoute('/dummies/{id}/subresources/{subresource}/recursivesubresource.{_format}', 'api_platform.action.get_subresource', DummyEntity::class, 'api_dummies_subresources_recursivesubresource_get_subresource', ['property' => 'recursivesubresource', 'identifiers' => [['id', DummyEntity::class, true, ['id']], ['subresource', RelatedDummyEntity::class, true, ['id']]], 'collection' => false, 'operationId' => 'api_dummies_subresources_recursivesubresource_get_subresource']),
             $routeCollection->get('api_dummies_subresources_recursivesubresource_get_subresource')
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/related_dummies/{id}/secondrecursivesubresource/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_related_dummies_secondrecursivesubresource_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', RelatedDummyEntity::class, true], ['secondrecursivesubresource', DummyEntity::class, false]], 'collection' => true, 'operationId' => 'api_related_dummies_secondrecursivesubresource_subresources_get_subresource']),
+            $this->getSubresourceRoute('/related_dummies/{id}/secondrecursivesubresource/subresources.{_format}', 'api_platform.action.get_subresource', RelatedDummyEntity::class, 'api_related_dummies_secondrecursivesubresource_subresources_get_subresource', ['property' => 'subresource', 'identifiers' => [['id', RelatedDummyEntity::class, true, ['id']], ['secondrecursivesubresource', DummyEntity::class, false, ['id']]], 'collection' => true, 'operationId' => 'api_related_dummies_secondrecursivesubresource_subresources_get_subresource']),
             $routeCollection->get('api_related_dummies_secondrecursivesubresource_subresources_get_subresource')
         );
 
         $this->assertEquals(
-            $this->getSubresourceRoute('/related_dummies/{id}/secondrecursivesubresource.{_format}', 'api_platform.action.get_subresource', DummyEntity::class, 'api_related_dummies_secondrecursivesubresource_get_subresource', ['property' => 'secondrecursivesubresource', 'identifiers' => [['id', RelatedDummyEntity::class, true]], 'collection' => false, 'operationId' => 'api_related_dummies_secondrecursivesubresource_get_subresource']),
+            $this->getSubresourceRoute('/related_dummies/{id}/secondrecursivesubresource.{_format}', 'api_platform.action.get_subresource', DummyEntity::class, 'api_related_dummies_secondrecursivesubresource_get_subresource', ['property' => 'secondrecursivesubresource', 'identifiers' => [['id', RelatedDummyEntity::class, true, ['id']]], 'collection' => false, 'operationId' => 'api_related_dummies_secondrecursivesubresource_get_subresource']),
             $routeCollection->get('api_related_dummies_secondrecursivesubresource_get_subresource')
         );
     }
@@ -301,9 +303,13 @@ private function getApiLoaderWithResourceMetadata(ResourceMetadata $resourceMeta
 
         $resourceMetadataFactory = $resourceMetadataFactoryProphecy->reveal();
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), new UnderscorePathSegmentNameGenerator());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+        $identifiersExtractor = $identifiersExtractorProphecy->reveal();
 
-        return new ApiLoader($kernelProphecy->reveal(), $resourceNameCollectionFactoryProphecy->reveal(), $resourceMetadataFactory, $operationPathResolver, $containerProphecy->reveal(), ['jsonld' => ['application/ld+json']], [], $subresourceOperationFactory, false, true, true, false, false);
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), new UnderscorePathSegmentNameGenerator(), $identifiersExtractor);
+
+        return new ApiLoader($kernelProphecy->reveal(), $resourceNameCollectionFactoryProphecy->reveal(), $resourceMetadataFactory, $operationPathResolver, $containerProphecy->reveal(), ['jsonld' => ['application/ld+json']], [], $subresourceOperationFactory, false, true, true, false, false, $identifiersExtractor);
     }
 
     private function getRoute(string $path, string $controller, string $resourceClass, string $operationName, array $methods, bool $collection = false, array $requirements = [], array $extraDefaults = ['_stateless' => null], array $options = [], string $host = '', array $schemes = [], string $condition = ''): Route
@@ -314,6 +320,8 @@ private function getRoute(string $path, string $controller, string $resourceClas
                 '_controller' => $controller,
                 '_format' => null,
                 '_api_resource_class' => $resourceClass,
+                '_api_identified_by' => ['id'],
+                '_api_has_composite_identifier' => false,
                 sprintf('_api_%s_operation_name', $collection ? 'collection' : 'item') => $operationName,
             ] + $extraDefaults,
             $requirements,
@@ -335,6 +343,8 @@ private function getSubresourceRoute(string $path, string $controller, string $r
                 '_api_resource_class' => $resourceClass,
                 '_api_subresource_operation_name' => $operationName,
                 '_api_subresource_context' => $context,
+                '_api_identified_by' => ['id'],
+                '_api_has_composite_identifier' => false,
             ] + $extraDefaults,
             $requirements,
             [],
diff --git a/tests/Bridge/Symfony/Routing/IriConverterTest.php b/tests/Bridge/Symfony/Routing/IriConverterTest.php
index dbf51036f9b..96cf660e91f 100644
--- a/tests/Bridge/Symfony/Routing/IriConverterTest.php
+++ b/tests/Bridge/Symfony/Routing/IriConverterTest.php
@@ -24,7 +24,7 @@
 use ApiPlatform\Core\Exception\InvalidArgumentException;
 use ApiPlatform\Core\Exception\InvalidIdentifierException;
 use ApiPlatform\Core\Exception\ItemNotFoundException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
+use ApiPlatform\Core\Identifier\IdentifierDenormalizerInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
@@ -76,6 +76,7 @@ public function testGetItemFromIriCollectionRouteException()
         $routerProphecy->match('/users')->willReturn([
             '_api_resource_class' => Dummy::class,
             '_api_collection_operation_name' => 'get',
+            '_api_identified_by' => ['id'],
         ])->shouldBeCalledTimes(1);
 
         $converter = $this->getIriConverter($routerProphecy);
@@ -89,13 +90,14 @@ public function testGetItemFromIriItemNotFoundException()
 
         $itemDataProviderProphecy = $this->prophesize(ItemDataProviderInterface::class);
         $itemDataProviderProphecy
-            ->getItem(Dummy::class, 3, 'get', [])
+            ->getItem(Dummy::class, ['id' => 3], 'get', [])
             ->shouldBeCalled()->willReturn(null);
 
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->match('/users/3')->willReturn([
             '_api_resource_class' => Dummy::class,
             '_api_item_operation_name' => 'get',
+            '_api_identified_by' => ['id'],
             'id' => 3,
         ])->shouldBeCalledTimes(1);
 
@@ -107,12 +109,13 @@ public function testGetItemFromIri()
     {
         $item = new \stdClass();
         $itemDataProviderProphecy = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProviderProphecy->getItem(Dummy::class, 3, 'get', ['fetch_data' => true])->shouldBeCalled()->willReturn($item);
+        $itemDataProviderProphecy->getItem(Dummy::class, ['id' => 3], 'get', ['fetch_data' => true])->shouldBeCalled()->willReturn($item);
 
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->match('/users/3')->willReturn([
             '_api_resource_class' => Dummy::class,
             '_api_item_operation_name' => 'get',
+            '_api_identified_by' => ['id'],
             'id' => 3,
         ])->shouldBeCalledTimes(1);
 
@@ -123,7 +126,7 @@ public function testGetItemFromIri()
     public function testGetItemFromIriWithOperationName()
     {
         $itemDataProviderProphecy = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProviderProphecy->getItem('AppBundle\Entity\User', '3', 'operation_name', ['fetch_data' => true])
+        $itemDataProviderProphecy->getItem('AppBundle\Entity\User', ['id' => 3], 'operation_name', ['fetch_data' => true])
             ->willReturn('foo')
             ->shouldBeCalledTimes(1);
 
@@ -131,6 +134,7 @@ public function testGetItemFromIriWithOperationName()
         $routerProphecy->match('/users/3')->willReturn([
             '_api_resource_class' => 'AppBundle\Entity\User',
             '_api_item_operation_name' => 'operation_name',
+            '_api_identified_by' => ['id'],
             'id' => 3,
         ])->shouldBeCalledTimes(1);
 
@@ -215,7 +219,10 @@ public function testGetItemIriFromResourceClass()
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->generate('api_dummies_get_item', ['id' => 1], UrlGeneratorInterface::ABS_PATH)->willReturn('/dummies/1');
 
-        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy);
+        $resourceMetadataFactoryProphecy = $this->prophesize(ResourceMetadataFactoryInterface::class);
+        $resourceMetadataFactoryProphecy->create(Dummy::class)->willReturn((new ResourceMetadata())->withAttributes(['composite_identifier' => true]));
+
+        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, null, null, $resourceMetadataFactoryProphecy->reveal());
         $this->assertEquals($converter->getItemIriFromResourceClass(Dummy::class, ['id' => 1]), '/dummies/1');
     }
 
@@ -245,7 +252,10 @@ public function testNotAbleToGenerateGetItemIriFromResourceClass()
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->generate('dummies', ['id' => 1], UrlGeneratorInterface::ABS_PATH)->willThrow(new RouteNotFoundException());
 
-        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy);
+        $resourceMetadataFactoryProphecy = $this->prophesize(ResourceMetadataFactoryInterface::class);
+        $resourceMetadataFactoryProphecy->create(Dummy::class)->willReturn((new ResourceMetadata())->withAttributes(['composite_identifier' => true]));
+
+        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, null, null, $resourceMetadataFactoryProphecy->reveal());
         $converter->getItemIriFromResourceClass(Dummy::class, ['id' => 1]);
     }
 
@@ -253,24 +263,25 @@ public function testGetItemFromIriWithIdentifierConverter()
     {
         $item = new \stdClass();
         $itemDataProviderProphecy = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProviderProphecy->getItem(Dummy::class, ['id' => 3], 'get', ['fetch_data' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true])->shouldBeCalled()->willReturn($item);
-        $identifierConverterProphecy = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverterProphecy->convert('3', Dummy::class)->shouldBeCalled()->willReturn(['id' => 3]);
+        $itemDataProviderProphecy->getItem(Dummy::class, ['id' => 3], 'get', ['fetch_data' => true])->shouldBeCalled()->willReturn($item);
+        $identifierDenormalizerProphecy = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierDenormalizerProphecy->denormalize(['id' => '3'], Dummy::class)->shouldBeCalled()->willReturn(['id' => 3]);
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->match('/users/3')->willReturn([
             '_api_resource_class' => Dummy::class,
             '_api_item_operation_name' => 'get',
+            '_api_identified_by' => ['id'],
             'id' => 3,
         ])->shouldBeCalledTimes(1);
 
-        $converter = $this->getIriConverter($routerProphecy, null, $itemDataProviderProphecy, null, $identifierConverterProphecy);
+        $converter = $this->getIriConverter($routerProphecy, null, $itemDataProviderProphecy, null, $identifierDenormalizerProphecy);
         $this->assertEquals($converter->getItemFromIri('/users/3', ['fetch_data' => true]), $item);
     }
 
     public function testGetItemFromIriWithSubresourceDataProvider()
     {
         $item = new \stdClass();
-        $subresourceContext = ['identifiers' => [['id', Dummy::class, true]]];
+        $subresourceContext = ['identifiers' => [['id', Dummy::class, true, ['id']]]];
         $routeNameResolverProphecy = $this->prophesize(RouteNameResolverInterface::class);
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->match('/users/3/adresses')->willReturn([
@@ -280,7 +291,7 @@ public function testGetItemFromIriWithSubresourceDataProvider()
             'id' => 3,
         ])->shouldBeCalledTimes(1);
         $subresourceDataProviderProphecy = $this->prophesize(SubresourceDataProviderInterface::class);
-        $subresourceDataProviderProphecy->getSubresource(Dummy::class, ['id' => 3], $subresourceContext + ['fetch_data' => true], 'get_subresource')->shouldBeCalled()->willReturn($item);
+        $subresourceDataProviderProphecy->getSubresource(Dummy::class, ['id' => ['id' => 3]], $subresourceContext + ['fetch_data' => true], 'get_subresource')->shouldBeCalled()->willReturn($item);
         $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, $subresourceDataProviderProphecy);
         $this->assertEquals($converter->getItemFromIri('/users/3/adresses', ['fetch_data' => true]), $item);
     }
@@ -290,7 +301,7 @@ public function testGetItemFromIriWithSubresourceDataProviderNotFound()
         $this->expectException(ItemNotFoundException::class);
         $this->expectExceptionMessage('Item not found for "/users/3/adresses".');
 
-        $subresourceContext = ['identifiers' => [['id', Dummy::class, true]]];
+        $subresourceContext = ['identifiers' => [['id', Dummy::class, true, ['id']]]];
         $routeNameResolverProphecy = $this->prophesize(RouteNameResolverInterface::class);
         $routerProphecy = $this->prophesize(RouterInterface::class);
         $routerProphecy->match('/users/3/adresses')->willReturn([
@@ -299,11 +310,11 @@ public function testGetItemFromIriWithSubresourceDataProviderNotFound()
             '_api_subresource_operation_name' => 'get_subresource',
             'id' => 3,
         ])->shouldBeCalledTimes(1);
-        $identifierConverterProphecy = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverterProphecy->convert('3', Dummy::class)->shouldBeCalled()->willReturn(['id' => 3]);
+        $identifierDenormalizerProphecy = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierDenormalizerProphecy->denormalize(['id' => '3'], Dummy::class)->shouldBeCalled()->willReturn(['id' => 3]);
         $subresourceDataProviderProphecy = $this->prophesize(SubresourceDataProviderInterface::class);
-        $subresourceDataProviderProphecy->getSubresource(Dummy::class, ['id' => ['id' => 3]], $subresourceContext + ['fetch_data' => true, IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true], 'get_subresource')->shouldBeCalled()->willReturn(null);
-        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, $subresourceDataProviderProphecy, $identifierConverterProphecy);
+        $subresourceDataProviderProphecy->getSubresource(Dummy::class, ['id' => ['id' => 3]], $subresourceContext + ['fetch_data' => true], 'get_subresource')->shouldBeCalled()->willReturn(null);
+        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, $subresourceDataProviderProphecy, $identifierDenormalizerProphecy);
         $converter->getItemFromIri('/users/3/adresses', ['fetch_data' => true]);
     }
 
@@ -318,52 +329,15 @@ public function testGetItemFromIriBadIdentifierException()
         $routerProphecy->match('/users/3')->willReturn([
             '_api_resource_class' => Dummy::class,
             '_api_item_operation_name' => 'get_subresource',
+            '_api_identified_by' => ['id'],
             'id' => 3,
         ])->shouldBeCalledTimes(1);
-        $identifierConverterProphecy = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverterProphecy->convert('3', Dummy::class)->shouldBeCalled()->willThrow(new InvalidIdentifierException('Item not found for "/users/3".'));
-        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, null, $identifierConverterProphecy);
+        $identifierDenormalizerProphecy = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierDenormalizerProphecy->denormalize(['id' => 3], Dummy::class)->shouldBeCalled()->willThrow(new InvalidIdentifierException('Item not found for "/users/3".'));
+        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy, null, null, $identifierDenormalizerProphecy);
         $this->assertEquals($converter->getItemFromIri('/users/3', ['fetch_data' => true]), $item);
     }
 
-    public function testNoIdentifiersException()
-    {
-        $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('No identifiers defined for resource of type "\App\Entity\Sample"');
-
-        $routeNameResolverProphecy = $this->prophesize(RouteNameResolverInterface::class);
-        $routerProphecy = $this->prophesize(RouterInterface::class);
-
-        $converter = $this->getIriConverter($routerProphecy, $routeNameResolverProphecy);
-
-        $method = new \ReflectionMethod(IriConverter::class, 'generateIdentifiersUrl');
-        $method->setAccessible(true);
-        $method->invoke($converter, [], '\App\Entity\Sample');
-    }
-
-    /**
-     * @group legacy
-     * @expectedDeprecation Not injecting "ApiPlatform\Core\Api\IdentifiersExtractorInterface" is deprecated since API Platform 2.1 and will not be possible anymore in API Platform 3
-     * @expectedDeprecation Not injecting ApiPlatform\Core\Api\ResourceClassResolverInterface in the IdentifiersExtractor might introduce cache issues with object identifiers.
-     */
-    public function testLegacyConstructor()
-    {
-        $propertyNameCollectionFactoryProphecy = $this->prophesize(PropertyNameCollectionFactoryInterface::class);
-        $propertyMetadataFactoryProphecy = $this->prophesize(PropertyMetadataFactoryInterface::class);
-        $routerProphecy = $this->prophesize(RouterInterface::class);
-        $routeNameResolverProphecy = $this->prophesize(RouteNameResolverInterface::class);
-        $itemDataProviderProphecy = $this->prophesize(ItemDataProviderInterface::class);
-
-        new IriConverter(
-            $propertyNameCollectionFactoryProphecy->reveal(),
-            $propertyMetadataFactoryProphecy->reveal(),
-            $itemDataProviderProphecy->reveal(),
-            $routeNameResolverProphecy->reveal(),
-            $routerProphecy->reveal(),
-            null
-        );
-    }
-
     private function getResourceClassResolver()
     {
         $resourceClassResolver = $this->prophesize(ResourceClassResolverInterface::class);
@@ -374,7 +348,7 @@ private function getResourceClassResolver()
         return $resourceClassResolver->reveal();
     }
 
-    private function getIriConverter($routerProphecy = null, $routeNameResolverProphecy = null, $itemDataProviderProphecy = null, $subresourceDataProviderProphecy = null, $identifierConverterProphecy = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
+    private function getIriConverter($routerProphecy = null, $routeNameResolverProphecy = null, $itemDataProviderProphecy = null, $subresourceDataProviderProphecy = null, $identifierDenormalizerProphecy = null, ResourceMetadataFactoryInterface $resourceMetadataFactory = null)
     {
         $propertyNameCollectionFactoryProphecy = $this->prophesize(PropertyNameCollectionFactoryInterface::class);
         $propertyMetadataFactoryProphecy = $this->prophesize(PropertyMetadataFactoryInterface::class);
@@ -392,16 +366,20 @@ private function getIriConverter($routerProphecy = null, $routeNameResolverProph
         $propertyNameCollectionFactory = $propertyNameCollectionFactoryProphecy->reveal();
         $propertyMetadataFactory = $propertyMetadataFactoryProphecy->reveal();
 
+        if (null === $identifierDenormalizerProphecy) {
+            $identifierDenormalizerProphecy = $this->prophesize(IdentifierDenormalizerInterface::class);
+            $identifierDenormalizerProphecy->denormalize(Argument::type('array'), Argument::type('string'))->will(function ($args) {
+                return $args[0];
+            });
+        }
+
         return new IriConverter(
-            $propertyNameCollectionFactory,
-            $propertyMetadataFactory,
             $itemDataProvider->reveal(),
             $routeNameResolverProphecy->reveal(),
             $routerProphecy->reveal(),
-            null,
             new IdentifiersExtractor($propertyNameCollectionFactory, $propertyMetadataFactory, null, $this->getResourceClassResolver()),
             $subresourceDataProviderProphecy ? $subresourceDataProviderProphecy->reveal() : null,
-            $identifierConverterProphecy ? $identifierConverterProphecy->reveal() : null,
+            $identifierDenormalizerProphecy->reveal(),
             null,
             $resourceMetadataFactory
         );
diff --git a/tests/DataProvider/ChainItemDataProviderTest.php b/tests/DataProvider/ChainItemDataProviderTest.php
index a226e5a3113..3bb53c40f60 100644
--- a/tests/DataProvider/ChainItemDataProviderTest.php
+++ b/tests/DataProvider/ChainItemDataProviderTest.php
@@ -14,11 +14,9 @@
 namespace ApiPlatform\Core\Tests\DataProvider;
 
 use ApiPlatform\Core\DataProvider\ChainItemDataProvider;
-use ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\ItemDataProviderInterface;
 use ApiPlatform\Core\DataProvider\RestrictedDataProviderInterface;
 use ApiPlatform\Core\Exception\ResourceClassNotSupportedException;
-use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\CompositePrimitiveItem;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy;
 use ApiPlatform\Core\Tests\ProphecyTrait;
 use PHPUnit\Framework\TestCase;
@@ -37,34 +35,6 @@ public function testGetItem()
         $dummy = new Dummy();
         $dummy->setName('Lucie');
 
-        $firstDataProvider = $this->prophesize(DenormalizedIdentifiersAwareItemDataProviderInterface::class);
-        $firstDataProvider->willImplement(RestrictedDataProviderInterface::class);
-        $firstDataProvider->supports(Dummy::class, null, [])->willReturn(false);
-
-        $secondDataProvider = $this->prophesize(DenormalizedIdentifiersAwareItemDataProviderInterface::class);
-        $secondDataProvider->willImplement(RestrictedDataProviderInterface::class);
-        $secondDataProvider->supports(Dummy::class, null, [])->willReturn(true);
-        $secondDataProvider->getItem(Dummy::class, ['id' => 1], null, [])->willReturn($dummy);
-
-        $thirdDataProvider = $this->prophesize(DenormalizedIdentifiersAwareItemDataProviderInterface::class);
-        $thirdDataProvider->willImplement(RestrictedDataProviderInterface::class);
-        $thirdDataProvider->supports(Dummy::class, null, [])->willReturn(true);
-        $thirdDataProvider->getItem(Dummy::class, ['id' => 1], null, [])->willReturn(new \stdClass());
-
-        $chainItemDataProvider = new ChainItemDataProvider([
-            $firstDataProvider->reveal(),
-            $secondDataProvider->reveal(),
-            $thirdDataProvider->reveal(),
-        ]);
-
-        $this->assertEquals($dummy, $chainItemDataProvider->getItem(Dummy::class, ['id' => 1]));
-    }
-
-    public function testGetItemWithoutDenormalizedIdentifiers()
-    {
-        $dummy = new Dummy();
-        $dummy->setName('Lucie');
-
         $firstDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $firstDataProvider->willImplement(RestrictedDataProviderInterface::class);
         $firstDataProvider->supports(Dummy::class, null, [])->willReturn(false);
@@ -72,12 +42,12 @@ public function testGetItemWithoutDenormalizedIdentifiers()
         $secondDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $secondDataProvider->willImplement(RestrictedDataProviderInterface::class);
         $secondDataProvider->supports(Dummy::class, null, [])->willReturn(true);
-        $secondDataProvider->getItem(Dummy::class, '1', null, [])->willReturn($dummy);
+        $secondDataProvider->getItem(Dummy::class, ['id' => 1], null, [])->willReturn($dummy);
 
         $thirdDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $thirdDataProvider->willImplement(RestrictedDataProviderInterface::class);
         $thirdDataProvider->supports(Dummy::class, null, [])->willReturn(true);
-        $thirdDataProvider->getItem(Dummy::class, 1, null, [])->willReturn(new \stdClass());
+        $thirdDataProvider->getItem(Dummy::class, ['id' => 1], null, [])->willReturn(new \stdClass());
 
         $chainItemDataProvider = new ChainItemDataProvider([
             $firstDataProvider->reveal(),
@@ -96,7 +66,7 @@ public function testGetItemExceptions()
 
         $chainItemDataProvider = new ChainItemDataProvider([$firstDataProvider->reveal()]);
 
-        $this->assertEquals('', $chainItemDataProvider->getItem('notfound', 1));
+        $this->assertEquals('', $chainItemDataProvider->getItem('notfound', ['id' => 1]));
     }
 
     /**
@@ -109,37 +79,17 @@ public function testLegacyGetItem()
         $dummy->setName('Lucie');
 
         $firstDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $firstDataProvider->getItem(Dummy::class, 1, null, [])->willThrow(ResourceClassNotSupportedException::class);
+        $firstDataProvider->getItem(Dummy::class, ['test' => 1], null, [])->willThrow(ResourceClassNotSupportedException::class);
 
         $secondDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $secondDataProvider->getItem(Dummy::class, 1, null, [])->willReturn($dummy);
+        $secondDataProvider->getItem(Dummy::class, ['test' => 1], null, [])->willReturn($dummy);
 
         $thirdDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $thirdDataProvider->getItem(Dummy::class, 1, null, [])->willReturn(new \stdClass());
+        $thirdDataProvider->getItem(Dummy::class, ['test' => 1], null, [])->willReturn(new \stdClass());
 
         $chainItemDataProvider = new ChainItemDataProvider([$firstDataProvider->reveal(), $secondDataProvider->reveal(), $thirdDataProvider->reveal()]);
 
-        $chainItemDataProvider->getItem(Dummy::class, 1);
-    }
-
-    /**
-     * @group legacy
-     * @expectedDeprecation Receiving "$id" as non-array in an item data provider is deprecated in 2.3 in favor of implementing "ApiPlatform\Core\DataProvider\DenormalizedIdentifiersAwareItemDataProviderInterface".
-     */
-    public function testLegacyGetItemWithoutDenormalizedIdentifiersAndCompositeIdentifier()
-    {
-        $dummy = new CompositePrimitiveItem('Lucie', 1984);
-
-        $dataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $dataProvider->willImplement(RestrictedDataProviderInterface::class);
-        $dataProvider->supports(CompositePrimitiveItem::class, null, [])->willReturn(true);
-        $dataProvider->getItem(CompositePrimitiveItem::class, 'name=Lucie;year=1984', null, [])->willReturn($dummy);
-
-        $chainItemDataProvider = new ChainItemDataProvider([
-            $dataProvider->reveal(),
-        ]);
-
-        $this->assertEquals($dummy, $chainItemDataProvider->getItem(CompositePrimitiveItem::class, ['name' => 'Lucie', 'year' => 1984]));
+        $chainItemDataProvider->getItem(Dummy::class, ['test' => 1]);
     }
 
     /**
@@ -149,10 +99,10 @@ public function testLegacyGetItemWithoutDenormalizedIdentifiersAndCompositeIdent
     public function testLegacyGetItemExceptions()
     {
         $firstDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $firstDataProvider->getItem('notfound', 1, null, [])->willThrow(ResourceClassNotSupportedException::class);
+        $firstDataProvider->getItem('notfound', ['test' => 1], null, [])->willThrow(ResourceClassNotSupportedException::class);
 
         $chainItemDataProvider = new ChainItemDataProvider([$firstDataProvider->reveal()]);
 
-        $this->assertEquals('', $chainItemDataProvider->getItem('notfound', 1));
+        $this->assertEquals('', $chainItemDataProvider->getItem('notfound', ['test' => 1]));
     }
 }
diff --git a/tests/EventListener/DeserializeListenerTest.php b/tests/EventListener/DeserializeListenerTest.php
index 6563567b420..602ed2ee4eb 100644
--- a/tests/EventListener/DeserializeListenerTest.php
+++ b/tests/EventListener/DeserializeListenerTest.php
@@ -200,13 +200,7 @@ public function testDeserializeResourceClassSupportedFormat(string $method, bool
     public function testLegacyDeserializeResourceClassSupportedFormat(string $method, bool $populateObject): void
     {
         $formatsProviderProphecy = $this->prophesize(FormatsProviderInterface::class);
-        $formatsProviderProphecy->getFormatsFromAttributes([
-            'resource_class' => 'Foo',
-            'collection_operation_name' => 'post',
-            'receive' => true,
-            'respond' => true,
-            'persist' => true,
-        ])->willReturn(self::FORMATS)->shouldBeCalled();
+        $formatsProviderProphecy->getFormatsFromAttributes(Argument::type('array'))->willReturn(self::FORMATS)->shouldBeCalled();
 
         $this->doTestDeserializeResourceClassSupportedFormat($method, $populateObject, $formatsProviderProphecy->reveal());
     }
@@ -216,7 +210,7 @@ private function doTestDeserializeResourceClassSupportedFormat(string $method, b
         $result = $populateObject ? new \stdClass() : null;
         $eventProphecy = $this->prophesize(RequestEvent::class);
 
-        $request = new Request([], [], ['data' => $result, '_api_resource_class' => 'Foo', '_api_collection_operation_name' => 'post'], [], [], [], '{}');
+        $request = new Request([], [], ['data' => $result, '_api_resource_class' => 'Foo', '_api_collection_operation_name' => 'post', '_api_identified_by'], [], [], [], '{}');
         $request->setMethod($method);
         $request->headers->set('Content-Type', 'application/json');
         $eventProphecy->getRequest()->willReturn($request)->shouldBeCalled();
diff --git a/tests/EventListener/ReadListenerTest.php b/tests/EventListener/ReadListenerTest.php
index a809dfdd537..b07245d74e6 100644
--- a/tests/EventListener/ReadListenerTest.php
+++ b/tests/EventListener/ReadListenerTest.php
@@ -19,7 +19,7 @@
 use ApiPlatform\Core\EventListener\ReadListener;
 use ApiPlatform\Core\Exception\InvalidIdentifierException;
 use ApiPlatform\Core\Exception\RuntimeException;
-use ApiPlatform\Core\Identifier\IdentifierConverterInterface;
+use ApiPlatform\Core\Identifier\IdentifierDenormalizerInterface;
 use ApiPlatform\Core\Metadata\Resource\Factory\ResourceMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Resource\ResourceMetadata;
 use ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity\Dummy;
@@ -39,7 +39,7 @@ class ReadListenerTest extends TestCase
 
     public function testNotAnApiPlatformRequest()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
@@ -89,7 +89,7 @@ public function testDoNotReadWhenReceiveFlagIsFalse()
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
         $subresourceDataProvider->getSubresource(Argument::cetera())->shouldNotBeCalled();
 
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
 
         $request = new Request([], [], ['id' => 1, 'data' => new Dummy(), '_api_resource_class' => Dummy::class, '_api_item_operation_name' => 'put', '_api_receive' => false]);
         $request->setMethod('PUT');
@@ -112,7 +112,7 @@ public function testDoNotReadWhenDisabledInOperationAttribute()
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
         $subresourceDataProvider->getSubresource(Argument::cetera())->shouldNotBeCalled();
 
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
 
         $resourceMetadata = new ResourceMetadata('Dummy', null, null, [
             'put' => [
@@ -135,7 +135,7 @@ public function testDoNotReadWhenDisabledInOperationAttribute()
 
     public function testRetrieveCollectionPost()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
@@ -161,7 +161,7 @@ public function testRetrieveCollectionPost()
 
     public function testRetrieveCollectionGet()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection('Foo', 'get', ['filters' => ['foo' => 'bar']])->willReturn([])->shouldBeCalled();
@@ -187,20 +187,20 @@ public function testRetrieveCollectionGet()
 
     public function testRetrieveItem()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert('1', 'Foo')->shouldBeCalled()->willReturn(['id' => '1']);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '1'], 'Foo')->shouldBeCalled()->willReturn(['id' => '1']);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
 
         $data = new \stdClass();
         $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProvider->getItem('Foo', ['id' => '1'], 'get', [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true])->willReturn($data)->shouldBeCalled();
+        $itemDataProvider->getItem('Foo', ['id' => '1'], 'get', [])->willReturn($data)->shouldBeCalled();
 
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
         $subresourceDataProvider->getSubresource()->shouldNotBeCalled();
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json']);
+        $request = new Request([], [], ['id' => '1', '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_identified_by' => ['id'], '_api_format' => 'json', '_api_mime_type' => 'application/json']);
         $request->setMethod('GET');
 
         $event = $this->prophesize(RequestEvent::class);
@@ -213,35 +213,10 @@ public function testRetrieveItem()
         $this->assertEquals($data, $request->attributes->get('previous_data'));
     }
 
-    public function testRetrieveItemNoIdentifier()
-    {
-        $this->expectException(NotFoundHttpException::class);
-
-        $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
-        $collectionDataProvider->getCollection()->shouldNotBeCalled();
-
-        $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProvider->getItem()->shouldNotBeCalled();
-
-        $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
-        $subresourceDataProvider->getSubresource()->shouldNotBeCalled();
-
-        $request = new Request([], [], ['_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json']);
-        $request->setMethod('GET');
-
-        $event = $this->prophesize(RequestEvent::class);
-        $event->getRequest()->willReturn($request)->shouldBeCalled();
-
-        $listener = new ReadListener($collectionDataProvider->reveal(), $itemDataProvider->reveal(), $subresourceDataProvider->reveal());
-        $listener->onKernelRequest($event->reveal());
-
-        $request->attributes->get('data');
-    }
-
     public function testRetrieveSubresource()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert('1', 'Bar')->shouldBeCalled()->willReturn(['id' => '1']);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '1'], 'Foo')->shouldBeCalled()->willReturn(['id' => '1']);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
@@ -251,9 +226,9 @@ public function testRetrieveSubresource()
 
         $data = [new \stdClass()];
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
-        $subresourceDataProvider->getSubresource('Foo', ['id' => ['id' => '1']], ['identifiers' => [['id', 'Bar', true]], 'property' => 'bar', IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true], 'get')->willReturn($data)->shouldBeCalled();
+        $subresourceDataProvider->getSubresource('Foo', ['id' => ['id' => '1']], ['identifiers' => [['id', 'Bar', true, ['id']]], 'property' => 'bar'], 'get')->willReturn($data)->shouldBeCalled();
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true]], 'property' => 'bar']]);
+        $request = new Request([], [], ['id' => '1', '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true, ['id']]], 'property' => 'bar']]);
         $request->setMethod('GET');
 
         $event = $this->prophesize(RequestEvent::class);
@@ -269,6 +244,8 @@ public function testRetrieveSubresource()
     public function testRetrieveSubresourceNoDataProvider()
     {
         $this->expectException(RuntimeException::class);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '1'], 'Foo')->shouldBeCalled()->willReturn(['id' => '1']);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
@@ -276,13 +253,13 @@ public function testRetrieveSubresourceNoDataProvider()
         $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $itemDataProvider->getItem()->shouldNotBeCalled();
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true]], 'property' => 'bar']]);
+        $request = new Request([], [], ['id' => '1', '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true, ['id']]], 'property' => 'bar']]);
         $request->setMethod('GET');
 
         $event = $this->prophesize(RequestEvent::class);
         $event->getRequest()->willReturn($request)->shouldBeCalled();
 
-        $listener = new ReadListener($collectionDataProvider->reveal(), $itemDataProvider->reveal());
+        $listener = new ReadListener($collectionDataProvider->reveal(), $itemDataProvider->reveal(), null, null, $identifierConverter->reveal());
         $listener->onKernelRequest($event->reveal());
 
         $request->attributes->get('data');
@@ -290,8 +267,8 @@ public function testRetrieveSubresourceNoDataProvider()
 
     public function testRetrieveSubresourceNotFound()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert('1', 'Bar')->willThrow(new InvalidIdentifierException())->shouldBeCalled();
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '1'], 'Foo')->willThrow(new InvalidIdentifierException())->shouldBeCalled();
         $this->expectException(NotFoundHttpException::class);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
@@ -300,7 +277,7 @@ public function testRetrieveSubresourceNotFound()
         $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $itemDataProvider->getItem()->shouldNotBeCalled();
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true]], 'property' => 'bar']]);
+        $request = new Request([], [], ['id' => '1', '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true, ['id']]], 'property' => 'bar']]);
         $request->setMethod('GET');
 
         $event = $this->prophesize(RequestEvent::class);
@@ -312,18 +289,18 @@ public function testRetrieveSubresourceNotFound()
 
     public function testRetrieveItemNotFound()
     {
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert('22', 'Foo')->shouldBeCalled()->willReturn(['id' => 22]);
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '22'], 'Foo')->shouldBeCalled()->willReturn(['id' => 22]);
         $this->expectException(NotFoundHttpException::class);
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
 
         $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
-        $itemDataProvider->getItem('Foo', ['id' => 22], 'get', [IdentifierConverterInterface::HAS_IDENTIFIER_CONVERTER => true])->willReturn(null)->shouldBeCalled();
+        $itemDataProvider->getItem('Foo', ['id' => 22], 'get', [])->willReturn(null)->shouldBeCalled();
 
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
 
-        $request = new Request([], [], ['id' => 22, '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json']);
+        $request = new Request([], [], ['id' => '22', '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_identified_by' => ['id'], '_api_format' => 'json', '_api_mime_type' => 'application/json']);
         $request->setMethod('GET');
 
         $event = $this->prophesize(RequestEvent::class);
@@ -337,14 +314,14 @@ public function testRetrieveBadItemNormalizedIdentifiers()
     {
         $this->expectException(NotFoundHttpException::class);
 
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert('1', 'Foo')->shouldBeCalled()->willThrow(new InvalidIdentifierException());
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(['id' => '1'], 'Foo')->shouldBeCalled()->willThrow(new InvalidIdentifierException());
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $itemDataProvider = $this->prophesize(ItemDataProviderInterface::class);
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json']);
+        $request = new Request([], [], ['id' => '1', '_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_identified_by' => ['id'], '_api_format' => 'json', '_api_mime_type' => 'application/json']);
         $request->setMethod(Request::METHOD_GET);
 
         $event = $this->prophesize(RequestEvent::class);
@@ -358,8 +335,8 @@ public function testRetrieveBadSubresourceNormalizedIdentifiers()
     {
         $this->expectException(NotFoundHttpException::class);
 
-        $identifierConverter = $this->prophesize(IdentifierConverterInterface::class);
-        $identifierConverter->convert(Argument::type('string'), Argument::type('string'))->shouldBeCalled()->willThrow(new InvalidIdentifierException());
+        $identifierConverter = $this->prophesize(IdentifierDenormalizerInterface::class);
+        $identifierConverter->denormalize(Argument::type('array'), Argument::type('string'))->shouldBeCalled()->willThrow(new InvalidIdentifierException());
 
         $collectionDataProvider = $this->prophesize(CollectionDataProviderInterface::class);
         $collectionDataProvider->getCollection()->shouldNotBeCalled();
@@ -370,7 +347,7 @@ public function testRetrieveBadSubresourceNormalizedIdentifiers()
         $subresourceDataProvider = $this->prophesize(SubresourceDataProviderInterface::class);
         $subresourceDataProvider->getSubresource()->shouldNotBeCalled();
 
-        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true]], 'property' => 'bar']]);
+        $request = new Request([], [], ['id' => 1, '_api_resource_class' => 'Foo', '_api_subresource_operation_name' => 'get', '_api_format' => 'json', '_api_mime_type' => 'application/json', '_api_subresource_context' => ['identifiers' => [['id', 'Bar', true, ['id']]], 'property' => 'bar']]);
         $request->setMethod(Request::METHOD_GET);
 
         $event = $this->prophesize(RequestEvent::class);
diff --git a/tests/Fixtures/TestBundle/Action/ConfigCustom.php b/tests/Fixtures/TestBundle/Action/ConfigCustom.php
index c3e1b8811fa..32b5f21d83b 100644
--- a/tests/Fixtures/TestBundle/Action/ConfigCustom.php
+++ b/tests/Fixtures/TestBundle/Action/ConfigCustom.php
@@ -35,6 +35,6 @@ public function __invoke(Request $request, $id)
     {
         $attributes = RequestAttributesExtractor::extractAttributes($request);
 
-        return $this->dataProvider->getItem($attributes['resource_class'], $id);
+        return $this->dataProvider->getItem($attributes['resource_class'], ['id' => $id]);
     }
 }
diff --git a/tests/Fixtures/TestBundle/Controller/MongoDbOdm/CustomActionController.php b/tests/Fixtures/TestBundle/Controller/MongoDbOdm/CustomActionController.php
index 32baf7aa352..046834e2465 100644
--- a/tests/Fixtures/TestBundle/Controller/MongoDbOdm/CustomActionController.php
+++ b/tests/Fixtures/TestBundle/Controller/MongoDbOdm/CustomActionController.php
@@ -28,7 +28,7 @@ class CustomActionController extends AbstractController
      *     methods={"GET"},
      *     name="custom_normalization",
      *     path="/custom/{id}/normalization",
-     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization"}
+     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization", "_api_identified_by"={"id"}}
      * )
      */
     public function customNormalizationAction(CustomActionDummy $data)
@@ -67,7 +67,7 @@ public function customDenormalizationAction(Request $request)
      *     methods={"GET"},
      *     name="short_custom_normalization",
      *     path="/short_custom/{id}/normalization",
-     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization"}
+     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization", "_api_identified_by"={"id"}}
      * )
      */
     public function shortCustomNormalizationAction(CustomActionDummy $data)
diff --git a/tests/Fixtures/TestBundle/Controller/Orm/CustomActionController.php b/tests/Fixtures/TestBundle/Controller/Orm/CustomActionController.php
index 33145ad9461..b8eab18bfba 100644
--- a/tests/Fixtures/TestBundle/Controller/Orm/CustomActionController.php
+++ b/tests/Fixtures/TestBundle/Controller/Orm/CustomActionController.php
@@ -28,7 +28,7 @@ class CustomActionController extends AbstractController
      *     methods={"GET"},
      *     name="custom_normalization",
      *     path="/custom/{id}/normalization",
-     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization"}
+     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization", "_api_identified_by"={"id"}}
      * )
      */
     public function customNormalizationAction(CustomActionDummy $data)
@@ -67,7 +67,7 @@ public function customDenormalizationAction(Request $request)
      *     methods={"GET"},
      *     name="short_custom_normalization",
      *     path="/short_custom/{id}/normalization",
-     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization"}
+     *     defaults={"_api_resource_class"=CustomActionDummy::class, "_api_item_operation_name"="custom_normalization", "_api_identified_by"={"id"}}
      * )
      */
     public function shortCustomNormalizationAction(CustomActionDummy $data)
diff --git a/tests/Fixtures/TestBundle/DataProvider/ContainNonResourceItemDataProvider.php b/tests/Fixtures/TestBundle/DataProvider/ContainNonResourceItemDataProvider.php
index e83e2826ee0..d1c277650d8 100644
--- a/tests/Fixtures/TestBundle/DataProvider/ContainNonResourceItemDataProvider.php
+++ b/tests/Fixtures/TestBundle/DataProvider/ContainNonResourceItemDataProvider.php
@@ -32,18 +32,18 @@ public function supports(string $resourceClass, string $operationName = null, ar
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
-        if (!is_scalar($id)) {
+        if (!is_scalar($identifiers['id'])) {
             throw new \InvalidArgumentException('The id must be a scalar.');
         }
 
         // Retrieve the blog post item from somewhere
         $cnr = new $resourceClass();
-        $cnr->id = $id;
+        $cnr->id = $identifiers['id'];
         $cnr->notAResource = new NotAResource('f1', 'b1');
         $cnr->nested = new $resourceClass();
-        $cnr->nested->id = "$id-nested";
+        $cnr->nested->id = "{$identifiers['id']}-nested";
         $cnr->nested->notAResource = new NotAResource('f2', 'b2');
 
         return $cnr;
diff --git a/tests/Fixtures/TestBundle/DataProvider/ProductItemDataProvider.php b/tests/Fixtures/TestBundle/DataProvider/ProductItemDataProvider.php
index 242539f9a02..2ffd1c0e7a6 100644
--- a/tests/Fixtures/TestBundle/DataProvider/ProductItemDataProvider.php
+++ b/tests/Fixtures/TestBundle/DataProvider/ProductItemDataProvider.php
@@ -42,10 +42,10 @@ public function supports(string $resourceClass, string $operationName = null, ar
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         return $this->managerRegistry->getRepository($this->orm ? Product::class : ProductDocument::class)->findOneBy([
-            'code' => $id,
+            'code' => $identifiers['code'],
         ]);
     }
 }
diff --git a/tests/Fixtures/TestBundle/DataProvider/ResourceInterfaceImplementationDataProvider.php b/tests/Fixtures/TestBundle/DataProvider/ResourceInterfaceImplementationDataProvider.php
index dd994ac5f0c..db23d2a7ce4 100644
--- a/tests/Fixtures/TestBundle/DataProvider/ResourceInterfaceImplementationDataProvider.php
+++ b/tests/Fixtures/TestBundle/DataProvider/ResourceInterfaceImplementationDataProvider.php
@@ -26,9 +26,9 @@ public function supports(string $resourceClass, string $operationName = null, ar
         return ResourceInterface::class === $resourceClass;
     }
 
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
-        if ('some-id' === $id) {
+        if ('some-id' === $identifiers['foo']) {
             return (new ResourceInterfaceImplementation())->setFoo('single item');
         }
 
diff --git a/tests/Fixtures/TestBundle/DataProvider/SerializableItemDataProvider.php b/tests/Fixtures/TestBundle/DataProvider/SerializableItemDataProvider.php
index 6b5e8b8823a..b7686862fdf 100644
--- a/tests/Fixtures/TestBundle/DataProvider/SerializableItemDataProvider.php
+++ b/tests/Fixtures/TestBundle/DataProvider/SerializableItemDataProvider.php
@@ -29,7 +29,7 @@ class SerializableItemDataProvider implements ItemDataProviderInterface, Restric
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         return $this->getSerializer()->deserialize(<<<'JSON'
 {
diff --git a/tests/Fixtures/TestBundle/DataProvider/TaxonItemDataProvider.php b/tests/Fixtures/TestBundle/DataProvider/TaxonItemDataProvider.php
index 7e1c9d73f2b..68bd14acbe9 100644
--- a/tests/Fixtures/TestBundle/DataProvider/TaxonItemDataProvider.php
+++ b/tests/Fixtures/TestBundle/DataProvider/TaxonItemDataProvider.php
@@ -42,10 +42,10 @@ public function supports(string $resourceClass, string $operationName = null, ar
     /**
      * {@inheritdoc}
      */
-    public function getItem(string $resourceClass, $id, string $operationName = null, array $context = [])
+    public function getItem(string $resourceClass, array $identifiers, string $operationName = null, array $context = [])
     {
         return $this->managerRegistry->getRepository($this->orm ? Taxon::class : TaxonDocument::class)->findOneBy([
-            'code' => $id,
+            'code' => $identifiers['code'],
         ]);
     }
 }
diff --git a/tests/Fixtures/TestBundle/Document/Book.php b/tests/Fixtures/TestBundle/Document/Book.php
new file mode 100644
index 00000000000..098feacb68e
--- /dev/null
+++ b/tests/Fixtures/TestBundle/Document/Book.php
@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\Fixtures\TestBundle\Document;
+
+use ApiPlatform\Core\Annotation\ApiResource;
+use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
+
+/**
+ * Book.
+ *
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ *
+ * @ApiResource(collectionOperations={}, itemOperations={
+ *     "get",
+ *     "get_by_isbn"={"method"="GET", "path"="/books/by_isbn/{isbn}.{_format}", "requirements"={"isbn"=".+"}, "identified_by"="isbn"}
+ * })
+ * @ODM\Document
+ */
+class Book
+{
+    /**
+     * @ODM\Id(strategy="INCREMENT", type="integer")
+     */
+    private $id;
+
+    /**
+     * @ODM\Field(type="string", nullable=true)
+     */
+    public $name;
+
+    /**
+     * @ODM\Field(type="string")
+     */
+    public $isbn;
+
+    public function getId()
+    {
+        return $this->id;
+    }
+}
diff --git a/tests/Fixtures/TestBundle/Document/CustomMultipleIdentifierDummy.php b/tests/Fixtures/TestBundle/Document/CustomMultipleIdentifierDummy.php
new file mode 100644
index 00000000000..4bdc10a52d8
--- /dev/null
+++ b/tests/Fixtures/TestBundle/Document/CustomMultipleIdentifierDummy.php
@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\Fixtures\TestBundle\Document;
+
+use ApiPlatform\Core\Annotation\ApiProperty;
+use ApiPlatform\Core\Annotation\ApiResource;
+use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
+
+/**
+ * Custom Identifier Dummy.
+ *
+ * @ApiResource(compositeIdentifier=false)
+ * @ODM\Document
+ */
+class CustomMultipleIdentifierDummy
+{
+    /**
+     * @var int The custom identifier
+     *
+     * @ODM\Id(strategy="NONE", type="integer")
+     */
+    private $firstId;
+
+    /**
+     * @var int The custom identifier
+     *
+     * @ApiProperty(identifier=true)
+     * @ODM\Field(type="integer")
+     */
+    private $secondId;
+
+    /**
+     * @var string The dummy name
+     *
+     * @ODM\Field(type="string")
+     */
+    private $name;
+
+    public function getFirstId(): int
+    {
+        return $this->firstId;
+    }
+
+    public function setFirstId(int $firstId)
+    {
+        $this->firstId = $firstId;
+    }
+
+    public function getSecondId(): int
+    {
+        return $this->secondId;
+    }
+
+    public function setSecondId(int $secondId)
+    {
+        $this->secondId = $secondId;
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name)
+    {
+        $this->name = $name;
+    }
+}
diff --git a/tests/Fixtures/TestBundle/Entity/Book.php b/tests/Fixtures/TestBundle/Entity/Book.php
new file mode 100644
index 00000000000..fc6fa14ff19
--- /dev/null
+++ b/tests/Fixtures/TestBundle/Entity/Book.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity;
+
+use ApiPlatform\Core\Annotation\ApiResource;
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * Book.
+ *
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ *
+ * @ApiResource(collectionOperations={}, itemOperations={
+ *     "get",
+ *     "get_by_isbn"={"method"="GET", "path"="/books/by_isbn/{isbn}.{_format}", "requirements"={"isbn"=".+"}, "identified_by"="isbn"}
+ * })
+ * @ORM\Entity
+ */
+class Book
+{
+    /**
+     * @ORM\Column(type="integer")
+     * @ORM\Id
+     * @ORM\GeneratedValue(strategy="AUTO")
+     */
+    private $id;
+
+    /**
+     * @ORM\Column
+     */
+    public $name;
+
+    /**
+     * @ORM\Column(unique=true)
+     */
+    public $isbn;
+
+    public function getId()
+    {
+        return $this->id;
+    }
+}
diff --git a/tests/Fixtures/TestBundle/Entity/CustomMultipleIdentifierDummy.php b/tests/Fixtures/TestBundle/Entity/CustomMultipleIdentifierDummy.php
new file mode 100644
index 00000000000..82d77d8d2d0
--- /dev/null
+++ b/tests/Fixtures/TestBundle/Entity/CustomMultipleIdentifierDummy.php
@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\Fixtures\TestBundle\Entity;
+
+use ApiPlatform\Core\Annotation\ApiResource;
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * Custom Identifier Dummy.
+ *
+ * @ApiResource(compositeIdentifier=false)
+ * @ORM\Entity
+ */
+class CustomMultipleIdentifierDummy
+{
+    /**
+     * @var int The custom identifier
+     *
+     * @ORM\Column(type="integer")
+     * @ORM\Id
+     */
+    private $firstId;
+
+    /**
+     * @var int The custom identifier
+     *
+     * @ORM\Column(type="integer")
+     * @ORM\Id
+     */
+    private $secondId;
+
+    /**
+     * @var string The dummy name
+     *
+     * @ORM\Column(length=30)
+     */
+    private $name;
+
+    public function getFirstId(): int
+    {
+        return $this->firstId;
+    }
+
+    public function setFirstId(int $firstId)
+    {
+        $this->firstId = $firstId;
+    }
+
+    public function getSecondId(): int
+    {
+        return $this->secondId;
+    }
+
+    public function setSecondId(int $secondId)
+    {
+        $this->secondId = $secondId;
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name)
+    {
+        $this->name = $name;
+    }
+}
diff --git a/tests/Fixtures/TestBundle/Entity/SlugParentDummy.php b/tests/Fixtures/TestBundle/Entity/SlugParentDummy.php
index 722f5d94e93..926f6aac018 100644
--- a/tests/Fixtures/TestBundle/Entity/SlugParentDummy.php
+++ b/tests/Fixtures/TestBundle/Entity/SlugParentDummy.php
@@ -23,7 +23,7 @@
 /**
  * Custom Identifier Dummy With Subresource.
  *
- * @ApiResource
+ * @ApiResource(attributes={"identified_by"="slug"})
  * @ORM\Entity
  */
 class SlugParentDummy
diff --git a/tests/Fixtures/TestBundle/Model/ProductInterface.php b/tests/Fixtures/TestBundle/Model/ProductInterface.php
index 04b095817e5..74d2ab2e165 100644
--- a/tests/Fixtures/TestBundle/Model/ProductInterface.php
+++ b/tests/Fixtures/TestBundle/Model/ProductInterface.php
@@ -21,6 +21,7 @@
 /**
  * @ApiResource(
  *     shortName="Product",
+ *     attributes={"identified_by"="code"},
  *     normalizationContext={
  *         "groups"={"product_read"},
  *     },
diff --git a/tests/Fixtures/TestBundle/Model/TaxonInterface.php b/tests/Fixtures/TestBundle/Model/TaxonInterface.php
index e715e8d6348..de9543e92be 100644
--- a/tests/Fixtures/TestBundle/Model/TaxonInterface.php
+++ b/tests/Fixtures/TestBundle/Model/TaxonInterface.php
@@ -21,6 +21,7 @@
 /**
  * @ApiResource(
  *     shortName="Taxon",
+ *     attributes={"identified_by"="code"},
  *     normalizationContext={
  *         "groups"={"taxon_read"},
  *     },
diff --git a/tests/Fixtures/app/config/config_common.yml b/tests/Fixtures/app/config/config_common.yml
index dabcc50d797..3895668dfb4 100644
--- a/tests/Fixtures/app/config/config_common.yml
+++ b/tests/Fixtures/app/config/config_common.yml
@@ -44,7 +44,6 @@ api_platform:
     description: |
         This is a test API.
         Made with love
-    allow_plain_identifiers:           true
     formats:
         jsonld:                        ['application/ld+json']
         jsonhal:                       ['application/hal+json']
diff --git a/tests/GraphQl/Serializer/ItemNormalizerTest.php b/tests/GraphQl/Serializer/ItemNormalizerTest.php
index 2ce80292c7a..ea5a2025bc2 100644
--- a/tests/GraphQl/Serializer/ItemNormalizerTest.php
+++ b/tests/GraphQl/Serializer/ItemNormalizerTest.php
@@ -107,7 +107,6 @@ public function testNormalize()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -161,7 +160,6 @@ public function testNormalizeNoResolverData(): void
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -209,7 +207,6 @@ public function testDenormalize()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
diff --git a/tests/Hal/Serializer/ItemNormalizerTest.php b/tests/Hal/Serializer/ItemNormalizerTest.php
index 4a11361625f..4a4febdf40e 100644
--- a/tests/Hal/Serializer/ItemNormalizerTest.php
+++ b/tests/Hal/Serializer/ItemNormalizerTest.php
@@ -151,7 +151,6 @@ public function testNormalize()
             $nameConverter->reveal(),
             null,
             null,
-            false,
             [],
             [],
             null
@@ -218,7 +217,6 @@ public function testNormalizeWithoutCache()
             $nameConverter->reveal(),
             null,
             null,
-            false,
             [],
             [],
             null
@@ -298,7 +296,6 @@ public function testMaxDepth()
             null,
             $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader())),
             null,
-            false,
             [],
             [],
             null
diff --git a/tests/Identifier/IdentifierConverterTest.php b/tests/Identifier/IdentifierConverterTest.php
deleted file mode 100644
index effe2759411..00000000000
--- a/tests/Identifier/IdentifierConverterTest.php
+++ /dev/null
@@ -1,96 +0,0 @@
-<?php
-
-/*
- * This file is part of the API Platform project.
- *
- * (c) Kévin Dunglas <dunglas@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-declare(strict_types=1);
-
-namespace ApiPlatform\Core\Tests\Identifier;
-
-use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
-use ApiPlatform\Core\Identifier\IdentifierConverter;
-use ApiPlatform\Core\Identifier\Normalizer\DateTimeIdentifierDenormalizer;
-use ApiPlatform\Core\Identifier\Normalizer\IntegerDenormalizer;
-use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
-use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
-use ApiPlatform\Core\Tests\ProphecyTrait;
-use PHPUnit\Framework\TestCase;
-use Symfony\Component\PropertyInfo\Type;
-
-/**
- * @author Antoine Bluchet <soyuka@gmail.com>
- */
-class IdentifierConverterTest extends TestCase
-{
-    use ProphecyTrait;
-
-    public function testCompositeIdentifier()
-    {
-        $identifier = 'a=1;c=2;d=2015-04-05';
-        $class = 'Dummy';
-
-        $integerPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_INT));
-        $identifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true);
-        $dateIdentifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateTime::class));
-
-        $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
-        $propertyMetadataFactory->create($class, 'a')->shouldBeCalled()->willReturn($integerPropertyMetadata);
-        $propertyMetadataFactory->create($class, 'c')->shouldBeCalled()->willReturn($identifierPropertyMetadata);
-        $propertyMetadataFactory->create($class, 'd')->shouldBeCalled()->willReturn($dateIdentifierPropertyMetadata);
-
-        $identifiersExtractor = $this->prophesize(IdentifiersExtractorInterface::class);
-        $identifiersExtractor->getIdentifiersFromResourceClass($class)->willReturn(['a', 'c', 'd']);
-
-        $identifierDenormalizers = [new IntegerDenormalizer(), new DateTimeIdentifierDenormalizer()];
-
-        $identifierDenormalizer = new IdentifierConverter($identifiersExtractor->reveal(), $propertyMetadataFactory->reveal(), $identifierDenormalizers);
-
-        $result = $identifierDenormalizer->convert($identifier, $class);
-        $this->assertEquals(['a' => 1, 'c' => '2', 'd' => new \DateTime('2015-04-05')], $result);
-        $this->assertSame(1, $result['a']);
-    }
-
-    public function testSingleDateIdentifier()
-    {
-        $identifier = '2015-04-05';
-        $class = 'Dummy';
-
-        $dateIdentifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateTime::class));
-
-        $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
-        $propertyMetadataFactory->create($class, 'funkyid')->shouldBeCalled()->willReturn($dateIdentifierPropertyMetadata);
-
-        $identifiersExtractor = $this->prophesize(IdentifiersExtractorInterface::class);
-        $identifiersExtractor->getIdentifiersFromResourceClass($class)->willReturn(['funkyid']);
-
-        $identifierDenormalizers = [new DateTimeIdentifierDenormalizer()];
-        $identifierDenormalizer = new IdentifierConverter($identifiersExtractor->reveal(), $propertyMetadataFactory->reveal(), $identifierDenormalizers);
-
-        $this->assertEquals($identifierDenormalizer->convert($identifier, $class), ['funkyid' => new \DateTime('2015-04-05')]);
-    }
-
-    public function testIntegerIdentifier()
-    {
-        $identifier = '42';
-        $class = 'Dummy';
-
-        $integerIdentifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_INT));
-
-        $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
-        $propertyMetadataFactory->create($class, 'id')->shouldBeCalled()->willReturn($integerIdentifierPropertyMetadata);
-
-        $identifiersExtractor = $this->prophesize(IdentifiersExtractorInterface::class);
-        $identifiersExtractor->getIdentifiersFromResourceClass($class)->willReturn(['id']);
-
-        $identifierDenormalizers = [new IntegerDenormalizer()];
-        $identifierDenormalizer = new IdentifierConverter($identifiersExtractor->reveal(), $propertyMetadataFactory->reveal(), $identifierDenormalizers);
-
-        $this->assertSame(['id' => 42], $identifierDenormalizer->convert($identifier, $class));
-    }
-}
diff --git a/tests/Identifier/IdentifierDenormalizerTest.php b/tests/Identifier/IdentifierDenormalizerTest.php
new file mode 100644
index 00000000000..bd0b3980ac4
--- /dev/null
+++ b/tests/Identifier/IdentifierDenormalizerTest.php
@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\Identifier;
+
+use ApiPlatform\Core\Identifier\IdentifierDenormalizer;
+use ApiPlatform\Core\Identifier\Normalizer\DateTimeIdentifierDenormalizer;
+use ApiPlatform\Core\Identifier\Normalizer\IntegerDenormalizer;
+use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
+use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\PropertyInfo\Type;
+
+/**
+ * @author Antoine Bluchet <soyuka@gmail.com>
+ */
+class IdentifierDenormalizerTest extends TestCase
+{
+    public function testSingleDateIdentifier()
+    {
+        $identifiers = ['funkyid' => '2015-04-05'];
+        $class = 'Dummy';
+
+        $dateIdentifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_OBJECT, false, \DateTime::class));
+
+        $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
+        $propertyMetadataFactory->create($class, 'funkyid')->shouldBeCalled()->willReturn($dateIdentifierPropertyMetadata);
+
+        $identifierDenormalizers = [new DateTimeIdentifierDenormalizer()];
+        $identifierDenormalizer = new IdentifierDenormalizer($propertyMetadataFactory->reveal(), $identifierDenormalizers);
+
+        $this->assertEquals($identifierDenormalizer->denormalize($identifiers, $class), ['funkyid' => new \DateTime('2015-04-05')]);
+    }
+
+    public function testIntegerIdentifier()
+    {
+        $identifiers = ['id' => '42'];
+        $class = 'Dummy';
+
+        $integerIdentifierPropertyMetadata = (new PropertyMetadata())->withIdentifier(true)->withType(new Type(Type::BUILTIN_TYPE_INT));
+
+        $propertyMetadataFactory = $this->prophesize(PropertyMetadataFactoryInterface::class);
+        $propertyMetadataFactory->create($class, 'id')->shouldBeCalled()->willReturn($integerIdentifierPropertyMetadata);
+
+        $identifierDenormalizers = [new IntegerDenormalizer()];
+        $identifierDenormalizer = new IdentifierDenormalizer($propertyMetadataFactory->reveal(), $identifierDenormalizers);
+
+        $this->assertSame(['id' => 42], $identifierDenormalizer->denormalize($identifiers, $class));
+    }
+}
diff --git a/tests/OpenApi/Factory/OpenApiFactoryTest.php b/tests/OpenApi/Factory/OpenApiFactoryTest.php
index f960dc3a113..d7db82d2293 100644
--- a/tests/OpenApi/Factory/OpenApiFactoryTest.php
+++ b/tests/OpenApi/Factory/OpenApiFactoryTest.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Tests\OpenApi\Factory;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Bridge\Symfony\Routing\RouterOperationPathResolver;
 use ApiPlatform\Core\DataProvider\PaginationOptions;
 use ApiPlatform\Core\JsonSchema\Schema;
@@ -148,6 +149,9 @@ public function testInvoke(): void
         $schemaFactory = new SchemaFactory($typeFactory, $resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new CamelCaseToSnakeCaseNameConverter());
         $typeFactory->setSchemaFactory($schemaFactory);
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $factory = new OpenApiFactory(
             $resourceNameCollectionFactoryProphecy->reveal(),
             $resourceMetadataFactory,
@@ -169,7 +173,8 @@ public function testInvoke(): void
                     'name' => 'key',
                 ],
             ]),
-            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination')
+            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination'),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $dummySchema = new Schema('openapi');
@@ -524,6 +529,9 @@ public function testOverrideDocumentation()
         $schemaFactory = new SchemaFactory($typeFactory, $resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new CamelCaseToSnakeCaseNameConverter());
         $typeFactory->setSchemaFactory($schemaFactory);
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $factory = new OpenApiFactory(
             $resourceNameCollectionFactoryProphecy->reveal(),
             $resourceMetadataFactory,
@@ -545,7 +553,8 @@ public function testOverrideDocumentation()
                     'name' => 'key',
                 ],
             ]),
-            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination')
+            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination'),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $openApi = $factory(['base_url' => '/app_dev.php/']);
@@ -613,7 +622,11 @@ public function testSubresourceDocumentation()
         $propertyNameCollectionFactory = $propertyNameCollectionFactoryProphecy->reveal();
         $propertyMetadataFactory = $propertyMetadataFactoryProphecy->reveal();
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+        $identifiersExtractor = $identifiersExtractorProphecy->reveal();
+
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator(), $identifiersExtractor);
 
         $resourceNameCollectionFactoryProphecy = $this->prophesize(ResourceNameCollectionFactoryInterface::class);
         $resourceNameCollectionFactoryProphecy->create()->shouldBeCalled()->willReturn(new ResourceNameCollection([Question::class, Answer::class]));
@@ -644,7 +657,8 @@ public function testSubresourceDocumentation()
                     'name' => 'key',
                 ],
             ]),
-            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination')
+            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination'),
+            $identifiersExtractor
         );
 
         $openApi = $factory(['base_url', '/app_dev.php/']);
diff --git a/tests/OpenApi/Serializer/OpenApiNormalizerTest.php b/tests/OpenApi/Serializer/OpenApiNormalizerTest.php
index 30444db0e4c..321b46dd9a2 100644
--- a/tests/OpenApi/Serializer/OpenApiNormalizerTest.php
+++ b/tests/OpenApi/Serializer/OpenApiNormalizerTest.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Tests\OpenApi\Serializer;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\DataProvider\PaginationOptions;
 use ApiPlatform\Core\JsonSchema\SchemaFactory;
 use ApiPlatform\Core\JsonSchema\TypeFactory;
@@ -95,6 +96,9 @@ public function testNormalize()
         $schemaFactory = new SchemaFactory($typeFactory, $resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new CamelCaseToSnakeCaseNameConverter());
         $typeFactory->setSchemaFactory($schemaFactory);
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $factory = new OpenApiFactory(
             $resourceNameCollectionFactoryProphecy->reveal(),
             $resourceMetadataFactory,
@@ -116,7 +120,8 @@ public function testNormalize()
                     'name' => 'key',
                 ],
             ]),
-            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination')
+            new PaginationOptions(true, 'page', true, 'itemsPerPage', true, 'pagination'),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $openApi = $factory(['base_url' => '/app_dev.php/']);
diff --git a/tests/Operation/Factory/SubresourceOperationFactoryTest.php b/tests/Operation/Factory/SubresourceOperationFactoryTest.php
index c811b159097..8b53f873c4f 100644
--- a/tests/Operation/Factory/SubresourceOperationFactoryTest.php
+++ b/tests/Operation/Factory/SubresourceOperationFactoryTest.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Core\Tests\Operation\Factory;
 
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyMetadataFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\Factory\PropertyNameCollectionFactoryInterface;
 use ApiPlatform\Core\Metadata\Property\PropertyMetadata;
@@ -27,6 +28,7 @@
 use ApiPlatform\Core\Tests\Fixtures\RelatedDummyEntity;
 use ApiPlatform\Core\Tests\ProphecyTrait;
 use PHPUnit\Framework\TestCase;
+use Prophecy\Argument;
 
 /**
  * @author Antoine Bluchet <soyuka@gmail.com>
@@ -62,7 +64,10 @@ public function testCreate()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('anotherSubresource', false)->shouldBeCalled()->willReturn('another_subresource');
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $pathSegmentNameGeneratorProphecy->reveal());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $pathSegmentNameGeneratorProphecy->reveal(), $identifiersExtractorProphecy->reveal());
 
         $this->assertEquals([
             'api_dummy_entities_subresource_get_subresource' => [
@@ -71,8 +76,9 @@ public function testCreate()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -83,9 +89,10 @@ public function testCreate()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity', 'relatedDummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', RelatedDummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', RelatedDummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_another_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource/another_subresource.{_format}',
                 'operation_name' => 'subresource_another_subresource_get_subresource',
@@ -96,10 +103,11 @@ public function testCreate()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', RelatedDummyEntity::class, false],
-                    ['anotherSubresource', DummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', RelatedDummyEntity::class, false, ['id']],
+                    ['anotherSubresource', DummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_another_subresource_subcollections_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource/another_subresource/subcollections.{_format}',
                 'operation_name' => 'subresource_another_subresource_subcollections_get_subresource',
@@ -110,8 +118,9 @@ public function testCreate()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_get_subresource',
                 'path' => '/dummy_entities/{id}/subcollections.{_format}',
                 'operation_name' => 'subcollections_get_subresource',
@@ -122,9 +131,10 @@ public function testCreate()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity', 'relatedDummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subcollection', RelatedDummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subcollection', RelatedDummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_another_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subcollections/{subcollection}/another_subresource.{_format}',
                 'operation_name' => 'subcollections_another_subresource_get_subresource',
@@ -135,10 +145,11 @@ public function testCreate()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subcollection', RelatedDummyEntity::class, true],
-                    ['anotherSubresource', DummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subcollection', RelatedDummyEntity::class, true, ['id']],
+                    ['anotherSubresource', DummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_another_subresource_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subcollections/{subcollection}/another_subresource/subresource.{_format}',
                 'operation_name' => 'subcollections_another_subresource_subresource_get_subresource',
@@ -180,7 +191,10 @@ public function testCreateByOverriding()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('anotherSubresource', false)->shouldBeCalled()->willReturn('another_subresource');
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $pathSegmentNameGeneratorProphecy->reveal());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactoryProphecy->reveal(), $propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $pathSegmentNameGeneratorProphecy->reveal(), $identifiersExtractorProphecy->reveal());
 
         $this->assertEquals([
             'api_dummy_entities_subresource_get_subresource' => [
@@ -189,8 +203,9 @@ public function testCreateByOverriding()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -201,9 +216,10 @@ public function testCreateByOverriding()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity', 'relatedDummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', RelatedDummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', RelatedDummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_another_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource/another_subresource.{_format}',
                 'operation_name' => 'subresource_another_subresource_get_subresource',
@@ -214,10 +230,11 @@ public function testCreateByOverriding()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', RelatedDummyEntity::class, false],
-                    ['anotherSubresource', DummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', RelatedDummyEntity::class, false, ['id']],
+                    ['anotherSubresource', DummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_another_subresource_subcollections_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource/another_subresource/subcollections.{_format}',
                 'operation_name' => 'subresource_another_subresource_subcollections_get_subresource',
@@ -228,8 +245,9 @@ public function testCreateByOverriding()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_get_subresource',
                 'path' => '/dummy_entities/{id}/foobars',
                 'operation_name' => 'subcollections_get_subresource',
@@ -240,9 +258,10 @@ public function testCreateByOverriding()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity', 'relatedDummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subcollection', RelatedDummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subcollection', RelatedDummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_another_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/foobars/{subcollection}/another_foobar.{_format}',
                 'operation_name' => 'subcollections_another_subresource_get_subresource',
@@ -253,10 +272,11 @@ public function testCreateByOverriding()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subcollection', RelatedDummyEntity::class, true],
-                    ['anotherSubresource', DummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subcollection', RelatedDummyEntity::class, true, ['id']],
+                    ['anotherSubresource', DummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subcollections_another_subresource_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/foobars/{subcollection}/another_foobar/subresource.{_format}',
                 'operation_name' => 'subcollections_another_subresource_subresource_get_subresource',
@@ -286,11 +306,15 @@ public function testCreateWithMaxDepth()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresource');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
                 $resourceMetadataFactoryProphecy->reveal(),
                 $propertyNameCollectionFactoryProphecy->reveal(),
                 $propertyMetadataFactoryProphecy->reveal(),
-                $pathSegmentNameGeneratorProphecy->reveal()
+                $pathSegmentNameGeneratorProphecy->reveal(),
+                $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -300,8 +324,9 @@ public function testCreateWithMaxDepth()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -346,11 +371,15 @@ public function testCreateWithMaxDepthMultipleSubresources()
         $pathSegmentNameGeneratorProphecy->getSegmentName('secondSubresource', false)->shouldBeCalled()->willReturn('second_subresources');
         $pathSegmentNameGeneratorProphecy->getSegmentName('moreSubresource', false)->shouldBeCalled()->willReturn('mode_subresources');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -360,8 +389,9 @@ public function testCreateWithMaxDepthMultipleSubresources()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -372,8 +402,9 @@ public function testCreateWithMaxDepthMultipleSubresources()
                 'resource_class' => DummyValidatedEntity::class,
                 'shortNames' => ['dummyValidatedEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_second_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/second_subresources.{_format}',
                 'operation_name' => 'second_subresource_get_subresource',
@@ -384,9 +415,10 @@ public function testCreateWithMaxDepthMultipleSubresources()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyValidatedEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['secondSubresource', DummyValidatedEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['secondSubresource', DummyValidatedEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_second_subresource_more_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/second_subresources/mode_subresources.{_format}',
                 'operation_name' => 'second_subresource_more_subresource_get_subresource',
@@ -430,11 +462,15 @@ public function testCreateWithMaxDepthMultipleSubresourcesSameMaxDepth()
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresources');
         $pathSegmentNameGeneratorProphecy->getSegmentName('secondSubresource', false)->shouldBeCalled()->willReturn('second_subresources');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -444,8 +480,9 @@ public function testCreateWithMaxDepthMultipleSubresourcesSameMaxDepth()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -456,8 +493,9 @@ public function testCreateWithMaxDepthMultipleSubresourcesSameMaxDepth()
                 'resource_class' => DummyValidatedEntity::class,
                 'shortNames' => ['dummyValidatedEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_second_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/second_subresources.{_format}',
                 'operation_name' => 'second_subresource_get_subresource',
@@ -485,11 +523,15 @@ public function testCreateSelfReferencingSubresources()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresources');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -499,8 +541,9 @@ public function testCreateSelfReferencingSubresources()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -537,11 +580,15 @@ public function testCreateWithDifferentMaxDepthSelfReferencingSubresources()
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresources');
         $pathSegmentNameGeneratorProphecy->getSegmentName('secondSubresource', false)->shouldBeCalled()->willReturn('second_subresources');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -551,8 +598,9 @@ public function testCreateWithDifferentMaxDepthSelfReferencingSubresources()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -563,9 +611,10 @@ public function testCreateWithDifferentMaxDepthSelfReferencingSubresources()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', DummyEntity::class, false],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', DummyEntity::class, false, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_second_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources/second_subresources.{_format}',
                 'operation_name' => 'subresource_second_subresource_get_subresource',
@@ -576,8 +625,9 @@ public function testCreateWithDifferentMaxDepthSelfReferencingSubresources()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_second_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/second_subresources.{_format}',
                 'operation_name' => 'second_subresource_get_subresource',
@@ -606,11 +656,15 @@ public function testCreateWithEnd()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', true)->shouldBeCalled()->willReturn('subresource');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
                 $resourceMetadataFactoryProphecy->reveal(),
                 $propertyNameCollectionFactoryProphecy->reveal(),
                 $propertyMetadataFactoryProphecy->reveal(),
-                $pathSegmentNameGeneratorProphecy->reveal()
+                $pathSegmentNameGeneratorProphecy->reveal(),
+                $identifiersExtractorProphecy->reveal()
         );
 
         $result = $subresourceOperationFactory->create(DummyEntity::class);
@@ -621,8 +675,9 @@ public function testCreateWithEnd()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresources_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresources_get_subresource',
@@ -633,9 +688,10 @@ public function testCreateWithEnd()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity', 'relatedDummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
-                    ['subresource', RelatedDummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
+                    ['subresource', RelatedDummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresources_item_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource/{subresource}.{_format}',
                 'operation_name' => 'subresources_item_get_subresource',
@@ -664,11 +720,15 @@ public function testCreateWithEndButNoCollection()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresource');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
                 $resourceMetadataFactoryProphecy->reveal(),
                 $propertyNameCollectionFactoryProphecy->reveal(),
                 $propertyMetadataFactoryProphecy->reveal(),
-                $pathSegmentNameGeneratorProphecy->reveal()
+                $pathSegmentNameGeneratorProphecy->reveal(),
+                $identifiersExtractorProphecy->reveal()
         );
 
         $result = $subresourceOperationFactory->create(DummyEntity::class);
@@ -679,8 +739,9 @@ public function testCreateWithEndButNoCollection()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -710,11 +771,15 @@ public function testCreateWithRootResourcePrefix()
         $pathSegmentNameGeneratorProphecy->getSegmentName('dummyEntity')->shouldBeCalled()->willReturn('dummy_entities');
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresource');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -724,8 +789,9 @@ public function testCreateWithRootResourcePrefix()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/root_resource_prefix/dummy_entities/{id}/subresource.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -759,11 +825,15 @@ public function testCreateSelfReferencingSubresourcesWithSubresources()
         $pathSegmentNameGeneratorProphecy->getSegmentName('subresource', false)->shouldBeCalled()->willReturn('subresources');
         $pathSegmentNameGeneratorProphecy->getSegmentName('otherSubresource', false)->shouldBeCalled()->willReturn('other_subresources');
 
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
         $subresourceOperationFactory = new SubresourceOperationFactory(
             $resourceMetadataFactoryProphecy->reveal(),
             $propertyNameCollectionFactoryProphecy->reveal(),
             $propertyMetadataFactoryProphecy->reveal(),
-            $pathSegmentNameGeneratorProphecy->reveal()
+            $pathSegmentNameGeneratorProphecy->reveal(),
+            $identifiersExtractorProphecy->reveal()
         );
 
         $this->assertEquals([
@@ -773,8 +843,9 @@ public function testCreateSelfReferencingSubresourcesWithSubresources()
                 'resource_class' => DummyEntity::class,
                 'shortNames' => ['dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/subresources.{_format}',
                 'operation_name' => 'subresource_get_subresource',
@@ -785,8 +856,9 @@ public function testCreateSelfReferencingSubresourcesWithSubresources()
                 'resource_class' => RelatedDummyEntity::class,
                 'shortNames' => ['relatedDummyEntity', 'dummyEntity'],
                 'identifiers' => [
-                    ['id', DummyEntity::class, true],
+                    ['id', DummyEntity::class, true, ['id']],
                 ],
+                'identified_by' => ['id'],
                 'route_name' => 'api_dummy_entities_other_subresource_get_subresource',
                 'path' => '/dummy_entities/{id}/other_subresources.{_format}',
                 'operation_name' => 'other_subresource_get_subresource',
diff --git a/tests/PathResolver/OperationPathResolverTest.php b/tests/PathResolver/OperationPathResolverTest.php
new file mode 100644
index 00000000000..c664cef58b5
--- /dev/null
+++ b/tests/PathResolver/OperationPathResolverTest.php
@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Core\Tests\PathResolver;
+
+use ApiPlatform\Core\Api\OperationType;
+use ApiPlatform\Core\Operation\UnderscorePathSegmentNameGenerator;
+use ApiPlatform\Core\PathResolver\OperationPathResolver;
+use PHPUnit\Framework\TestCase;
+
+class OperationPathResolverTest extends TestCase
+{
+    public function testResolveItemOperationPath()
+    {
+        $operationPathResolver = new OperationPathResolver(new UnderscorePathSegmentNameGenerator());
+        $this->assertEquals('/foos/{id}.{_format}', $operationPathResolver->resolveOperationPath('Foo', [], OperationType::ITEM, 'get'));
+    }
+
+    public function testResolveItemOperationPathIdentifiedBy()
+    {
+        $operationPathResolver = new OperationPathResolver(new UnderscorePathSegmentNameGenerator());
+        $this->assertSame('/short_names/{isbn}.{_format}', $operationPathResolver->resolveOperationPath('ShortName', ['identified_by' => ['isbn']], OperationType::ITEM, 'get'));
+    }
+}
diff --git a/tests/Serializer/AbstractItemNormalizerTest.php b/tests/Serializer/AbstractItemNormalizerTest.php
index 7f81ac608df..d9309862707 100644
--- a/tests/Serializer/AbstractItemNormalizerTest.php
+++ b/tests/Serializer/AbstractItemNormalizerTest.php
@@ -113,7 +113,6 @@ public function testSupportNormalizationAndSupportDenormalization()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -180,7 +179,6 @@ public function testNormalize()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -242,7 +240,6 @@ public function testNormalizeWithSecuredProperty()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -315,7 +312,6 @@ public function testNormalizeReadableLinks()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -377,7 +373,6 @@ public function testDenormalize()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -439,7 +434,7 @@ public function testCanDenormalizeInputClassWithDifferentFieldsThanResourceClass
         $serializerProphecy->willImplement(DenormalizerInterface::class);
         $serializerProphecy->denormalize($data, DummyForAdditionalFieldsInput::class, 'json', $cleanedContextWithObjectToPopulate)->willReturn($dummyInputDto);
 
-        $normalizer = new class($propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $iriConverterProphecy->reveal(), $resourceClassResolverProphecy->reveal(), null, null, null, null, false, [], [$inputDataTransformerProphecy->reveal()], null, null) extends AbstractItemNormalizer {
+        $normalizer = new class($propertyNameCollectionFactoryProphecy->reveal(), $propertyMetadataFactoryProphecy->reveal(), $iriConverterProphecy->reveal(), $resourceClassResolverProphecy->reveal(), null, null, null, null, [], [$inputDataTransformerProphecy->reveal()], null, null) extends AbstractItemNormalizer {
         };
         $normalizer->setSerializer($serializerProphecy->reveal());
 
@@ -494,7 +489,6 @@ public function testDenormalizeWritableLinks()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -514,7 +508,7 @@ public function testDenormalizeWritableLinks()
     public function testBadRelationType()
     {
         $this->expectException(UnexpectedValueException::class);
-        $this->expectExceptionMessage('Expected IRI or nested document for attribute "relatedDummy", "integer" given.');
+        $this->expectExceptionMessage('Nested documents for attribute "relatedDummy" are not allowed. Use IRIs instead.');
 
         $data = [
             'relatedDummy' => 22,
@@ -556,7 +550,6 @@ public function testBadRelationType()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -614,7 +607,6 @@ public function testInnerDocumentNotAllowed()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -659,7 +651,6 @@ public function testBadType()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -701,7 +692,6 @@ public function testTypeChecksCanBeDisabled()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -747,7 +737,6 @@ public function testJsonAllowIntAsFloat()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -822,7 +811,6 @@ public function testDenormalizeBadKeyType()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -864,7 +852,6 @@ public function testNullable()
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -924,7 +911,6 @@ public function testChildInheritedProperty(): void
             null,
             null,
             null,
-            false,
             [],
             [],
             null,
@@ -940,6 +926,7 @@ public function testChildInheritedProperty(): void
 
     public function testDenormalizeRelationWithPlainId()
     {
+        static::markTestSkipped('Legacy plain identifiers.');
         $data = [
             'relatedDummy' => 1,
         ];
@@ -976,7 +963,6 @@ public function testDenormalizeRelationWithPlainId()
             null,
             null,
             $itemDataProviderProphecy->reveal(),
-            true,
             [],
             [],
             null,
@@ -993,6 +979,7 @@ public function testDenormalizeRelationWithPlainId()
 
     public function testDenormalizeRelationWithPlainIdNotFound()
     {
+        $this->markTestSkipped('Legacy plain identifiers.');
         $this->expectException(ItemNotFoundException::class);
         $this->expectExceptionMessage(sprintf('Item not found for resource "%s" with id "1".', RelatedDummy::class));
 
@@ -1039,7 +1026,6 @@ public function testDenormalizeRelationWithPlainIdNotFound()
             null,
             null,
             $itemDataProviderProphecy->reveal(),
-            true,
             [],
             [],
             null,
@@ -1052,6 +1038,7 @@ public function testDenormalizeRelationWithPlainIdNotFound()
 
     public function testDoNotDenormalizeRelationWithPlainIdWhenPlainIdentifiersAreNotAllowed()
     {
+        $this->markTestSkipped('Legacy plain identifiers.');
         $this->expectException(UnexpectedValueException::class);
         $this->expectExceptionMessage('Expected IRI or nested document for attribute "relatedDummy", "integer" given.');
 
@@ -1097,7 +1084,6 @@ public function testDoNotDenormalizeRelationWithPlainIdWhenPlainIdentifiersAreNo
             null,
             null,
             $itemDataProviderProphecy->reveal(),
-            false,
             [],
             [],
             null,
@@ -1184,7 +1170,6 @@ public function testNormalizationWithDataTransformer()
             null,
             null,
             $itemDataProviderProphecy->reveal(),
-            false,
             [],
             [$dataTransformerProphecy->reveal(), $secondDataTransformerProphecy->reveal()],
             $resourceMetadataFactoryProphecy->reveal(),
diff --git a/tests/Serializer/ItemNormalizerTest.php b/tests/Serializer/ItemNormalizerTest.php
index 7a097aae786..6da44661c18 100644
--- a/tests/Serializer/ItemNormalizerTest.php
+++ b/tests/Serializer/ItemNormalizerTest.php
@@ -105,7 +105,6 @@ public function testNormalize()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -144,7 +143,6 @@ public function testDenormalize()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -184,7 +182,6 @@ public function testDenormalizeWithIri()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -221,7 +218,6 @@ public function testDenormalizeWithIdAndUpdateNotAllowed()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -260,7 +256,6 @@ public function testDenormalizeWithIdAndNoResourceClass()
             null,
             null,
             null,
-            false,
             null,
             [],
             null
@@ -305,7 +300,6 @@ public function testNormalizeWithDataTransformers()
             null,
             null,
             null,
-            false,
             null,
             [$dataTransformer->reveal()],
             null
diff --git a/tests/Serializer/SerializerFilterContextBuilderTest.php b/tests/Serializer/SerializerFilterContextBuilderTest.php
index 72f8dbe4495..6973c39a096 100644
--- a/tests/Serializer/SerializerFilterContextBuilderTest.php
+++ b/tests/Serializer/SerializerFilterContextBuilderTest.php
@@ -150,6 +150,8 @@ public function testCreateFromRequestWithoutAttributes()
         $attributes = [
             'resource_class' => DummyGroup::class,
             'collection_operation_name' => 'get',
+            'identified_by' => null,
+            'has_composite_identifier' => false,
             'receive' => true,
             'respond' => true,
             'persist' => true,
diff --git a/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php b/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
index 30f1c0ffcb8..6106b145e07 100644
--- a/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
+++ b/tests/Swagger/Serializer/DocumentationNormalizerV2Test.php
@@ -14,6 +14,7 @@
 namespace ApiPlatform\Core\Tests\Swagger\Serializer;
 
 use ApiPlatform\Core\Api\FilterCollection;
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\OperationAwareFormatsProviderInterface;
 use ApiPlatform\Core\Api\OperationMethodResolverInterface;
 use ApiPlatform\Core\Api\OperationType;
@@ -2210,7 +2211,10 @@ private function doTestNormalizeWithSubResource(OperationAwareFormatsProviderInt
         $propertyNameCollectionFactory = $propertyNameCollectionFactoryProphecy->reveal();
         $propertyMetadataFactory = $propertyMetadataFactoryProphecy->reveal();
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator(), $identifiersExtractorProphecy->reveal());
 
         $normalizer = new DocumentationNormalizer(
             $resourceMetadataFactory,
diff --git a/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php b/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
index b900a0ae2c3..ff583940641 100644
--- a/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
+++ b/tests/Swagger/Serializer/DocumentationNormalizerV3Test.php
@@ -14,6 +14,7 @@
 namespace ApiPlatform\Core\Tests\Swagger\Serializer;
 
 use ApiPlatform\Core\Api\FilterCollection;
+use ApiPlatform\Core\Api\IdentifiersExtractorInterface;
 use ApiPlatform\Core\Api\OperationAwareFormatsProviderInterface;
 use ApiPlatform\Core\Api\OperationMethodResolverInterface;
 use ApiPlatform\Core\Api\OperationType;
@@ -2242,7 +2243,10 @@ private function doTestNormalizeWithSubResource(OperationAwareFormatsProviderInt
         $propertyNameCollectionFactory = $propertyNameCollectionFactoryProphecy->reveal();
         $propertyMetadataFactory = $propertyMetadataFactoryProphecy->reveal();
 
-        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator());
+        $identifiersExtractorProphecy = $this->prophesize(IdentifiersExtractorInterface::class);
+        $identifiersExtractorProphecy->getIdentifiersFromResourceClass(Argument::type('string'))->willReturn(['id']);
+
+        $subresourceOperationFactory = new SubresourceOperationFactory($resourceMetadataFactory, $propertyNameCollectionFactory, $propertyMetadataFactory, new UnderscorePathSegmentNameGenerator(), $identifiersExtractorProphecy->reveal());
 
         $normalizer = new DocumentationNormalizer(
             $resourceMetadataFactory,
diff --git a/tests/Util/RequestAttributesExtractorTest.php b/tests/Util/RequestAttributesExtractorTest.php
index 37b2d082467..248877244e3 100644
--- a/tests/Util/RequestAttributesExtractorTest.php
+++ b/tests/Util/RequestAttributesExtractorTest.php
@@ -33,6 +33,8 @@ public function testExtractCollectionAttributes()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -49,6 +51,8 @@ public function testExtractItemAttributes()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -65,6 +69,8 @@ public function testExtractReceive()
                 'receive' => false,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -78,6 +84,8 @@ public function testExtractReceive()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -91,6 +99,8 @@ public function testExtractReceive()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -107,6 +117,8 @@ public function testExtractRespond()
                 'receive' => true,
                 'respond' => false,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -120,6 +132,8 @@ public function testExtractRespond()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -133,6 +147,8 @@ public function testExtractRespond()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -149,6 +165,8 @@ public function testExtractPersist()
                 'receive' => true,
                 'respond' => true,
                 'persist' => false,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -162,6 +180,8 @@ public function testExtractPersist()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );
@@ -175,6 +195,26 @@ public function testExtractPersist()
                 'receive' => true,
                 'respond' => true,
                 'persist' => true,
+                'identified_by' => null,
+                'has_composite_identifier' => false,
+            ],
+            RequestAttributesExtractor::extractAttributes($request)
+        );
+    }
+
+    public function testExtractIdentifiedBy()
+    {
+        $request = new Request([], [], ['_api_resource_class' => 'Foo', '_api_item_operation_name' => 'get', '_api_identified_by' => ['test'], '_api_has_composite_identifier' => true]);
+
+        $this->assertEquals(
+            [
+                'resource_class' => 'Foo',
+                'item_operation_name' => 'get',
+                'receive' => true,
+                'respond' => true,
+                'persist' => true,
+                'identified_by' => ['test'],
+                'has_composite_identifier' => true,
             ],
             RequestAttributesExtractor::extractAttributes($request)
         );