diff --git a/lib/optimizely/config/datafile_project_config.rb b/lib/optimizely/config/datafile_project_config.rb
index d8d78975..25357133 100644
--- a/lib/optimizely/config/datafile_project_config.rb
+++ b/lib/optimizely/config/datafile_project_config.rb
@@ -223,8 +223,9 @@ def get_experiment_from_key(experiment_key)
       experiment = @experiment_key_map[experiment_key]
       return experiment if experiment
 
-      @logger.log Logger::ERROR, "Experiment key '#{experiment_key}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_key: experiment_key)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -238,8 +239,9 @@ def get_experiment_from_id(experiment_id)
       experiment = @experiment_id_map[experiment_id]
       return experiment if experiment
 
-      @logger.log Logger::ERROR, "Experiment id '#{experiment_id}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_id: experiment_id)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -253,8 +255,9 @@ def get_experiment_key(experiment_id)
       experiment = @experiment_id_map[experiment_id]
       return experiment['key'] unless experiment.nil?
 
-      @logger.log Logger::ERROR, "Experiment id '#{experiment_id}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_id: experiment_id)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -268,8 +271,9 @@ def get_event_from_key(event_key)
       event = @event_key_map[event_key]
       return event if event
 
-      @logger.log Logger::ERROR, "Event '#{event_key}' is not in datafile."
-      @error_handler.handle_error InvalidEventError
+      invalid_event_error = InvalidEventError.new(event_key)
+      @logger.log Logger::ERROR, invalid_event_error.message
+      @error_handler.handle_error invalid_event_error
       nil
     end
 
@@ -283,8 +287,9 @@ def get_audience_from_id(audience_id)
       audience = @audience_id_map[audience_id]
       return audience if audience
 
-      @logger.log Logger::ERROR, "Audience '#{audience_id}' is not in datafile."
-      @error_handler.handle_error InvalidAudienceError
+      invalid_audience_error = InvalidAudienceError.new(audience_id)
+      @logger.log Logger::ERROR, invalid_audience_error.message
+      @error_handler.handle_error invalid_audience_error
       nil
     end
 
@@ -308,13 +313,15 @@ def get_variation_from_id(experiment_key, variation_id)
         variation = variation_id_map[variation_id]
         return variation if variation
 
-        @logger.log Logger::ERROR, "Variation id '#{variation_id}' is not in datafile."
-        @error_handler.handle_error InvalidVariationError
+        invalid_variation_error = InvalidVariationError.new(variation_id: variation_id)
+        @logger.log Logger::ERROR, invalid_variation_error.message
+        @error_handler.handle_error invalid_variation_error
         return nil
       end
 
-      @logger.log Logger::ERROR, "Experiment key '#{experiment_key}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_key: experiment_key)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -331,13 +338,15 @@ def get_variation_from_id_by_experiment_id(experiment_id, variation_id)
         variation = variation_id_map_by_experiment_id[variation_id]
         return variation if variation
 
-        @logger.log Logger::ERROR, "Variation id '#{variation_id}' is not in datafile."
-        @error_handler.handle_error InvalidVariationError
+        invalid_variation_error = InvalidVariationError.new(variation_id: variation_id)
+        @logger.log Logger::ERROR, invalid_variation_error.message
+        @error_handler.handle_error invalid_variation_error
         return nil
       end
 
-      @logger.log Logger::ERROR, "Experiment id '#{experiment_id}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_id: experiment_id)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -354,13 +363,15 @@ def get_variation_id_from_key_by_experiment_id(experiment_id, variation_key)
         variation = variation_key_map[variation_key]
         return variation['id'] if variation
 
-        @logger.log Logger::ERROR, "Variation key '#{variation_key}' is not in datafile."
-        @error_handler.handle_error InvalidVariationError
+        invalid_variation_error = InvalidVariationError.new(variation_key: variation_key)
+        @logger.log Logger::ERROR, invalid_variation_error.message
+        @error_handler.handle_error invalid_variation_error
         return nil
       end
 
-      @logger.log Logger::ERROR, "Experiment id '#{experiment_id}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_id: experiment_id)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -377,13 +388,15 @@ def get_variation_id_from_key(experiment_key, variation_key)
         variation = variation_key_map[variation_key]
         return variation['id'] if variation
 
-        @logger.log Logger::ERROR, "Variation key '#{variation_key}' is not in datafile."
-        @error_handler.handle_error InvalidVariationError
+        invalid_variation_error = InvalidVariationError.new(variation_key: variation_key)
+        @logger.log Logger::ERROR, invalid_variation_error.message
+        @error_handler.handle_error invalid_variation_error
         return nil
       end
 
-      @logger.log Logger::ERROR, "Experiment key '#{experiment_key}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_key: experiment_key)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
       nil
     end
 
@@ -397,8 +410,9 @@ def get_whitelisted_variations(experiment_id)
       experiment = @experiment_id_map[experiment_id]
       return experiment['forcedVariations'] if experiment
 
-      @logger.log Logger::ERROR, "Experiment ID '#{experiment_id}' is not in datafile."
-      @error_handler.handle_error InvalidExperimentError
+      invalid_experiment_error = InvalidExperimentError.new(experiment_id: experiment_id)
+      @logger.log Logger::ERROR, invalid_experiment_error.message
+      @error_handler.handle_error invalid_experiment_error
     end
 
     def get_attribute_id(attribute_key)
@@ -420,8 +434,9 @@ def get_attribute_id(attribute_key)
       end
       return attribute_key if has_reserved_prefix
 
-      @logger.log Logger::ERROR, "Attribute key '#{attribute_key}' is not in datafile."
-      @error_handler.handle_error InvalidAttributeError
+      invalid_attribute_error = InvalidAttributeError.new(attribute_key)
+      @logger.log Logger::ERROR, invalid_attribute_error.message
+      @error_handler.handle_error invalid_attribute_error
       nil
     end
 
@@ -439,8 +454,9 @@ def variation_id_exists?(experiment_id, variation_id)
         variation = variation_id_map[variation_id]
         return true if variation
 
-        @logger.log Logger::ERROR, "Variation ID '#{variation_id}' is not in datafile."
-        @error_handler.handle_error InvalidVariationError
+        invalid_variation_error = InvalidVariationError.new(variation_id: variation_id)
+        @logger.log Logger::ERROR, invalid_variation_error.message
+        @error_handler.handle_error invalid_variation_error
       end
 
       false
diff --git a/lib/optimizely/exceptions.rb b/lib/optimizely/exceptions.rb
index 50ef62c0..5d608b2f 100644
--- a/lib/optimizely/exceptions.rb
+++ b/lib/optimizely/exceptions.rb
@@ -42,16 +42,28 @@ def initialize(msg = 'SDK key not provided/cannot be found in the datafile.')
   class InvalidAudienceError < Error
     # Raised when an invalid audience is provided
 
-    def initialize(msg = 'Provided audience is not in datafile.')
-      super
+    attr_reader :audience_id
+
+    def initialize(audience_id)
+      raise ArgumentError, 'audience_id must be provided' if audience_id.nil?
+
+      super("Audience id '#{audience_id}' is not in datafile.")
+
+      @audience_id = audience_id
     end
   end
 
   class InvalidAttributeError < Error
     # Raised when an invalid attribute is provided
 
-    def initialize(msg = 'Provided attribute is not in datafile.')
-      super
+    attr_reader :attribute_key
+
+    def initialize(attribute_key)
+      raise ArgumentError, 'attribute_key must be provided' if attribute_key.nil?
+
+      super("Attribute key '#{attribute_key}' is not in datafile.")
+
+      @attribute_key = attribute_key
     end
   end
 
@@ -74,24 +86,56 @@ def initialize(msg = 'Event tags provided are in an invalid format.')
   class InvalidExperimentError < Error
     # Raised when an invalid experiment key is provided
 
-    def initialize(msg = 'Provided experiment is not in datafile.')
-      super
+    attr_reader :experiment_id, :experiment_key
+
+    def initialize(experiment_id: nil, experiment_key: nil)
+      raise ArgumentError, 'Either experiment_id or experiment_key must be provided.' if experiment_id.nil? && experiment_key.nil?
+      raise ArgumentError, 'Cannot provide both experiment_id and experiment_key.' if !experiment_id.nil? && !experiment_key.nil?
+
+      if experiment_id.nil?
+        @experiment_key = experiment_key
+        identifier = "key '#{@experiment_key}'"
+      else
+        @experiment_id = experiment_id
+        identifier = "id '#{@experiment_id}'"
+      end
+
+      super("Experiment #{identifier} is not in datafile.")
     end
   end
 
   class InvalidEventError < Error
     # Raised when an invalid event key is provided
 
-    def initialize(msg = 'Provided event is not in datafile.')
-      super
+    attr_reader :event_key
+
+    def initialize(event_key)
+      raise ArgumentError, 'event_key must be provided.' if event_key.nil?
+
+      super("Event key '#{event_key}' is not in datafile.")
+
+      @event_key = event_key
     end
   end
 
   class InvalidVariationError < Error
     # Raised when an invalid variation key or ID is provided
 
-    def initialize(msg = 'Provided variation is not in datafile.')
-      super
+    attr_reader :variation_id, :variation_key
+
+    def initialize(variation_id: nil, variation_key: nil)
+      raise ArgumentError, 'Either variation_id or variation_key must be provided.' if variation_id.nil? && variation_key.nil?
+      raise ArgumentError, 'Cannot provide both variation_id and variation_key.' if !variation_id.nil? && !variation_key.nil?
+
+      if variation_id.nil?
+        identifier = "key '#{variation_key}'"
+        @variation_key = variation_key
+      else
+        identifier = "id '#{variation_id}'"
+        @variation_id = variation_id
+      end
+
+      super("Variation #{identifier} is not in datafile.")
     end
   end
 
diff --git a/spec/config/datafile_project_config_spec.rb b/spec/config/datafile_project_config_spec.rb
index 3cf2bd31..e30d07e1 100644
--- a/spec/config/datafile_project_config_spec.rb
+++ b/spec/config/datafile_project_config_spec.rb
@@ -837,14 +837,14 @@
     describe 'get_event_from_key' do
       it 'should log a message when provided event key is invalid' do
         config.get_event_from_key('invalid_key')
-        expect(spy_logger).to have_received(:log).with(Logger::ERROR, "Event 'invalid_key' is not in datafile.")
+        expect(spy_logger).to have_received(:log).with(Logger::ERROR, "Event key 'invalid_key' is not in datafile.")
       end
     end
 
     describe 'get_audience_from_id' do
       it 'should log a message when provided audience ID is invalid' do
         config.get_audience_from_id('invalid_id')
-        expect(spy_logger).to have_received(:log).with(Logger::ERROR, "Audience 'invalid_id' is not in datafile.")
+        expect(spy_logger).to have_received(:log).with(Logger::ERROR, "Audience id 'invalid_id' is not in datafile.")
       end
     end
 
@@ -948,7 +948,7 @@
       it 'should log a message when there is no experiment key map for the experiment' do
         config.get_whitelisted_variations('invalid_key')
         expect(spy_logger).to have_received(:log).with(Logger::ERROR,
-                                                       "Experiment ID 'invalid_key' is not in datafile.")
+                                                       "Experiment id 'invalid_key' is not in datafile.")
       end
     end