diff --git a/Sources/PostgREST/PostgrestBuilder.swift b/Sources/PostgREST/PostgrestBuilder.swift
index 1e6b733..649bc6f 100644
--- a/Sources/PostgREST/PostgrestBuilder.swift
+++ b/Sources/PostgREST/PostgrestBuilder.swift
@@ -30,7 +30,7 @@ public class PostgrestBuilder {
         }
 
         let session = URLSession.shared
-        let dataTask = session.dataTask(with: request, completionHandler: { [unowned self] (data, response, error) -> Void in
+        let dataTask = session.dataTask(with: request, completionHandler: { (data, response, error) -> Void in
             if let error = error {
                 completion(.failure(error))
                 return
@@ -47,8 +47,8 @@ public class PostgrestBuilder {
             }
 
             do {
-                try validate(data: data, response: response)
-                let response = try parse(data: data, response: response)
+                try Self.validate(data: data, response: response)
+                let response = try Self.parse(data: data, response: response, request: request)
                 completion(.success(response))
             } catch {
                 completion(.failure(error))
@@ -58,7 +58,7 @@ public class PostgrestBuilder {
         dataTask.resume()
     }
 
-    private func validate(data: Data, response: HTTPURLResponse) throws {
+    private static func validate(data: Data, response: HTTPURLResponse) throws {
         if 200 ..< 300 ~= response.statusCode {
             return
         }
@@ -70,11 +70,11 @@ public class PostgrestBuilder {
         throw PostgrestError(from: json) ?? PostgrestError(message: "failed to get error")
     }
 
-    private func parse(data: Data, response: HTTPURLResponse) throws -> PostgrestResponse {
+    private static func parse(data: Data, response: HTTPURLResponse, request: URLRequest) throws -> PostgrestResponse {
         var body: Any = data
         var count: Int?
 
-        if method == "HEAD" {
+        if request.httpMethod == "HEAD" {
             if let accept = response.allHeaderFields["Accept"] as? String, accept == "text/csv" {
                 body = data
             } else {
@@ -138,6 +138,9 @@ public class PostgrestBuilder {
         var request = URLRequest(url: url)
         request.httpMethod = method
         request.allHTTPHeaderFields = headers
+        if let body = body {
+            request.httpBody = try JSONSerialization.data(withJSONObject: body, options: [])
+        }
         return request
     }
 
diff --git a/Sources/PostgREST/PostgrestError.swift b/Sources/PostgREST/PostgrestError.swift
index a0505a2..7656b84 100644
--- a/Sources/PostgREST/PostgrestError.swift
+++ b/Sources/PostgREST/PostgrestError.swift
@@ -7,16 +7,13 @@ public struct PostgrestError: Error {
     public var message: String
 
     init?(from dictionary: [String: Any]) {
-        guard let details = dictionary["details"] as? String,
-              let hint = dictionary["hint"] as? String,
-              let code = dictionary["code"] as? String,
-              let message = dictionary["message"] as? String
-        else {
+        guard let message = dictionary["message"] as? String else {
             return nil
         }
-        self.details = details
-        self.hint = hint
-        self.code = code
+
+        self.details = dictionary["details"] as? String
+        self.hint = dictionary["hint"] as? String
+        self.code = dictionary["code"] as? String
         self.message = message
     }
 
diff --git a/Tests/PostgRESTTests/BuildURLRequestTests.swift b/Tests/PostgRESTTests/BuildURLRequestTests.swift
index 8c3d801..be77337 100644
--- a/Tests/PostgRESTTests/BuildURLRequestTests.swift
+++ b/Tests/PostgRESTTests/BuildURLRequestTests.swift
@@ -22,6 +22,11 @@ final class BuildURLRequestTests: XCTestCase {
                     .select()
                     .like(column: "email", value: "%@supabase.co")
                     .buildURLRequest(head: false, count: nil)
+            },
+            TestCase(name: "insert new user") { client in
+                try client.form("users")
+                    .insert(values: ["email": "johndoe@supabase.io"])
+                    .buildURLRequest(head: false, count: nil)
             }
         ]
 
diff --git a/Tests/PostgRESTTests/__Snapshots__/BuildURLRequestTests/testBuildURLRequest.insert-new-user.txt b/Tests/PostgRESTTests/__Snapshots__/BuildURLRequestTests/testBuildURLRequest.insert-new-user.txt
new file mode 100644
index 0000000..ed68a51
--- /dev/null
+++ b/Tests/PostgRESTTests/__Snapshots__/BuildURLRequestTests/testBuildURLRequest.insert-new-user.txt
@@ -0,0 +1,5 @@
+curl \
+	--request POST \
+	--header "Prefer: return=representation" \
+	--data "{\"email\":\"johndoe@supabase.io\"}" \
+	"https://example.supabase.co/users"
\ No newline at end of file