diff --git a/Splitio.Redis/Services/Client/Classes/RedisClient.cs b/Splitio.Redis/Services/Client/Classes/RedisClient.cs
index cb9acdc0..746d6319 100644
--- a/Splitio.Redis/Services/Client/Classes/RedisClient.cs
+++ b/Splitio.Redis/Services/Client/Classes/RedisClient.cs
@@ -122,7 +122,7 @@ private void BuildImpressionManager()
         {
             var shouldCalculatePreviousTime = _config.ImpressionsMode == ImpressionsMode.Optimized;
 
-            _impressionsManager = new ImpressionsManager(_impressionsLog, _customerImpressionListener, _impressionsCounter, shouldCalculatePreviousTime, _config.ImpressionsMode, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, _config.LabelsEnabled);
+            _impressionsManager = new ImpressionsManager(_impressionsLog, _customerImpressionListener, _impressionsCounter, shouldCalculatePreviousTime, _config.ImpressionsMode, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, _config.LabelsEnabled, _propertiesValidator);
         }
 
         private void BuildEventLog()
diff --git a/src/Splitio/Services/Client/Classes/JSONFileClient.cs b/src/Splitio/Services/Client/Classes/JSONFileClient.cs
index a3aacc2f..0efa534f 100644
--- a/src/Splitio/Services/Client/Classes/JSONFileClient.cs
+++ b/src/Splitio/Services/Client/Classes/JSONFileClient.cs
@@ -62,7 +62,7 @@ public JSONFileClient(string splitsFilePath,
             _uniqueKeysTracker = new NoopUniqueKeysTracker();
             _impressionsCounter = new NoopImpressionsCounter();
             _impressionsObserver = new NoopImpressionsObserver();
-            _impressionsManager = impressionsManager ?? new ImpressionsManager(impressionsLog, null, _impressionsCounter, false, ImpressionsMode.Debug, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, isLabelsEnabled);
+            _impressionsManager = impressionsManager ?? new ImpressionsManager(impressionsLog, null, _impressionsCounter, false, ImpressionsMode.Debug, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, isLabelsEnabled, _propertiesValidator);
 
             BuildClientExtension();
         }
diff --git a/src/Splitio/Services/Client/Classes/LocalhostClient.cs b/src/Splitio/Services/Client/Classes/LocalhostClient.cs
index b113952b..b232c817 100644
--- a/src/Splitio/Services/Client/Classes/LocalhostClient.cs
+++ b/src/Splitio/Services/Client/Classes/LocalhostClient.cs
@@ -67,7 +67,7 @@ public LocalhostClient(ConfigurationOptions configurationOptions) : base("localh
             _uniqueKeysTracker = new NoopUniqueKeysTracker();
             _impressionsCounter = new NoopImpressionsCounter();
             _impressionsObserver = new NoopImpressionsObserver();
-            _impressionsManager = new ImpressionsManager(null, null, _impressionsCounter, false, ImpressionsMode.Debug, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, false);
+            _impressionsManager = new ImpressionsManager(null, null, _impressionsCounter, false, ImpressionsMode.Debug, null, _tasksManager, _uniqueKeysTracker, _impressionsObserver, false, _propertiesValidator);
 
             BuildClientExtension();
 
diff --git a/src/Splitio/Services/Client/Classes/SelfRefreshingClient.cs b/src/Splitio/Services/Client/Classes/SelfRefreshingClient.cs
index 041b0e65..efcfec64 100644
--- a/src/Splitio/Services/Client/Classes/SelfRefreshingClient.cs
+++ b/src/Splitio/Services/Client/Classes/SelfRefreshingClient.cs
@@ -159,7 +159,7 @@ private void BuildImpressionsObserver()
 
         private void BuildImpressionManager()
         {
-            _impressionsManager = new ImpressionsManager(_impressionsLog, _customerImpressionListener, _impressionsCounter, true, _config.ImpressionsMode, _telemetryRuntimeProducer, _tasksManager, _uniqueKeysTracker, _impressionsObserver, _config.LabelsEnabled);
+            _impressionsManager = new ImpressionsManager(_impressionsLog, _customerImpressionListener, _impressionsCounter, true, _config.ImpressionsMode, _telemetryRuntimeProducer, _tasksManager, _uniqueKeysTracker, _impressionsObserver, _config.LabelsEnabled, _propertiesValidator);
         }
 
         private void BuildEventLog()
diff --git a/src/Splitio/Services/Client/Classes/SplitClient.cs b/src/Splitio/Services/Client/Classes/SplitClient.cs
index 9e677de8..b18fe01f 100644
--- a/src/Splitio/Services/Client/Classes/SplitClient.cs
+++ b/src/Splitio/Services/Client/Classes/SplitClient.cs
@@ -34,7 +34,7 @@ public abstract class SplitClient : ISplitClient
         protected readonly IKeyValidator _keyValidator;
         protected readonly ISplitNameValidator _splitNameValidator;
         protected readonly IEventTypeValidator _eventTypeValidator;
-        protected readonly IPropertiesValidator _eventPropertiesValidator;
+        protected readonly IPropertiesValidator _propertiesValidator;
         protected readonly IWrapperAdapter _wrapperAdapter;
         protected readonly IConfigService _configService;
         protected readonly IFlagSetsValidator _flagSetsValidator;
@@ -71,7 +71,7 @@ public SplitClient(string apikey)
             _keyValidator = new KeyValidator();
             _splitNameValidator = new SplitNameValidator();
             _eventTypeValidator = new EventTypeValidator();
-            _eventPropertiesValidator = new PropertiesValidator();
+            _propertiesValidator = new PropertiesValidator();
             _factoryInstantiationsService = FactoryInstantiationsService.Instance();
             _flagSetsValidator = new FlagSetsValidator();
             _configService = new ConfigService(_wrapperAdapter, _flagSetsValidator, new SdkMetadataValidator());
@@ -412,7 +412,7 @@ protected void BuildImpressionsCounter(BaseConfig config)
 
         protected void BuildClientExtension()
         {
-            _clientExtensionService = new ClientExtensionService(_blockUntilReadyService, _statusManager, _keyValidator, _splitNameValidator, _telemetryEvaluationProducer, _eventTypeValidator, _eventPropertiesValidator, _trafficTypeValidator, _flagSetsValidator, _flagSetsFilter);
+            _clientExtensionService = new ClientExtensionService(_blockUntilReadyService, _statusManager, _keyValidator, _splitNameValidator, _telemetryEvaluationProducer, _eventTypeValidator, _propertiesValidator, _trafficTypeValidator, _flagSetsValidator, _flagSetsFilter);
         }
 
         protected void BuildFlagSetsFilter(HashSet<string> sets)
@@ -520,13 +520,13 @@ private List<TreatmentResult> GetTreatmentsByFlagSets(Enums.API method, Key key,
             }
         }
 
-        private List<KeyImpression> BuildAndGetImpressions(List<TreatmentResult> treatments, Key key)
+        private List<KeyImpression> BuildAndGetImpressions(List<TreatmentResult> treatments, Key key, Dictionary<string, object> properties = null)
         {
             var impressions = new List<KeyImpression>();
 
             foreach (var treatment in treatments)
             {
-                var impression = _impressionsManager.Build(treatment, key);
+                var impression = _impressionsManager.Build(treatment, key, properties);
 
                 if (impression != null) impressions.Add(impression);
             }
diff --git a/src/Splitio/Services/Impressions/Classes/ImpressionsManager.cs b/src/Splitio/Services/Impressions/Classes/ImpressionsManager.cs
index 0e5bdb23..1ca7684a 100644
--- a/src/Splitio/Services/Impressions/Classes/ImpressionsManager.cs
+++ b/src/Splitio/Services/Impressions/Classes/ImpressionsManager.cs
@@ -1,5 +1,7 @@
-using Splitio.Domain;
+using Newtonsoft.Json;
+using Splitio.Domain;
 using Splitio.Services.Impressions.Interfaces;
+using Splitio.Services.InputValidation.Interfaces;
 using Splitio.Services.Logger;
 using Splitio.Services.Shared.Classes;
 using Splitio.Services.Tasks;
@@ -24,6 +26,7 @@ public class ImpressionsManager : IImpressionsManager
         private readonly ITasksManager _taskManager;
         private readonly ImpressionsMode _impressionsMode;
         private readonly IUniqueKeysTracker _uniqueKeysTracker;
+        private readonly IPropertiesValidator _propertiesValidator;
         private readonly bool _addPreviousTime;
         private readonly bool _labelsEnabled;
 
@@ -36,7 +39,8 @@ public ImpressionsManager(IImpressionsLog impressionsLog,
             ITasksManager taskManager,
             IUniqueKeysTracker uniqueKeysTracker,
             IImpressionsObserver impressionsObserver,
-            bool labelsEnabled)
+            bool labelsEnabled,
+            IPropertiesValidator propertiesValidator)
         {
             _impressionsLog = impressionsLog;
             _customerImpressionListener = customerImpressionListener;
@@ -48,14 +52,21 @@ public ImpressionsManager(IImpressionsLog impressionsLog,
             _impressionsMode = impressionsMode;
             _uniqueKeysTracker = uniqueKeysTracker;
             _labelsEnabled = labelsEnabled;
+            _propertiesValidator = propertiesValidator;
         }
 
         #region Public Methods
-        public KeyImpression Build(TreatmentResult result, Key key)
+        public KeyImpression Build(TreatmentResult result, Key key, Dictionary<string, object> properties)
         {
             if (Labels.SplitNotFound.Equals(result.Label)) return null;
 
             var impression = new KeyImpression(key.matchingKey, result.FeatureFlagName, result.Treatment, result.ImpTime, result.ChangeNumber, _labelsEnabled ? result.Label : null, key.bucketingKeyHadValue ? key.bucketingKey : null, result.ImpressionsDisabled);
+
+            var validatorResult = _propertiesValidator.IsValid(properties);
+            if (validatorResult.Success)
+            {
+                impression.Properties = JsonConvert.SerializeObject(validatorResult.Value);
+            }
             
             try
             {
@@ -64,19 +75,23 @@ public KeyImpression Build(TreatmentResult result, Key key)
                 {
                     _impressionsCounter.Inc(result.FeatureFlagName, result.ImpTime);
                     _uniqueKeysTracker.Track(key.matchingKey, result.FeatureFlagName);
-                } else if (_impressionsMode == ImpressionsMode.Debug)
-                {
-                    // In DEBUG mode we should calculate the pt only. 
-
-                    ShouldCalculatePreviousTime(impression);
-                } else if (_impressionsMode == ImpressionsMode.Optimized)
+                }
+                else if (string.IsNullOrEmpty(impression.Properties))
                 {
-                    // In OPTIMIZED mode we should track the total amount of evaluations and deduplicate the impressions.
-
-                    ShouldCalculatePreviousTime(impression);
-                    if (impression.PreviousTime.HasValue)
-                        _impressionsCounter.Inc(result.FeatureFlagName, result.ImpTime);
-                        impression.Optimized = ShouldQueueImpression(impression);
+                    switch (_impressionsMode)
+                    {
+                        case ImpressionsMode.Debug:
+                            // In DEBUG mode we should calculate the pt only.
+                            ShouldCalculatePreviousTime(impression);
+                            break;
+                        case ImpressionsMode.Optimized:
+                            // In OPTIMIZED mode we should track the total amount of evaluations and deduplicate the impressions.
+                            ShouldCalculatePreviousTime(impression);
+                            if (impression.PreviousTime.HasValue)
+                                _impressionsCounter.Inc(result.FeatureFlagName, result.ImpTime);
+                            impression.Optimized = ShouldQueueImpression(impression);
+                            break;
+                    }
                 }
             }
             catch (Exception ex)
@@ -165,20 +180,26 @@ private bool GetImpressionsToTrack(List<KeyImpression> impressions, out List<Key
                 .Where(i => !i.ImpressionsDisabled)
                 .ToList();
 
-            if (filteredImpressions.Count == 0) return false;
+            if (filteredImpressions.Count == 0)
+            {
+                return false;
+            }
 
             switch (_impressionsMode)
             {
                 case ImpressionsMode.Debug:
-                    impressionsToTrack.AddRange(filteredImpressions);
+                    impressionsToTrack = filteredImpressions;
                     break;
                 case ImpressionsMode.Optimized:
                 default:
-                    impressionsToTrack.AddRange(filteredImpressions.Where(i => i.Optimized).ToList());
-                    var deduped = filteredImpressions.Count - impressionsToTrack.Count;
-                    _telemetryRuntimeProducer?.RecordImpressionsStats(ImpressionsEnum.ImpressionsDeduped, deduped);
+                    impressionsToTrack = filteredImpressions
+                        .Where(i => i.Optimized || !string.IsNullOrEmpty(i.Properties))
+                        .ToList();
+
+                    _telemetryRuntimeProducer?.RecordImpressionsStats(ImpressionsEnum.ImpressionsDeduped, filteredImpressions.Count - impressionsToTrack.Count);
                     break;
             }
+
             return true;
         }
 
diff --git a/src/Splitio/Services/Impressions/Interfaces/IImpressionsManager.cs b/src/Splitio/Services/Impressions/Interfaces/IImpressionsManager.cs
index 8ce51b73..a194c734 100644
--- a/src/Splitio/Services/Impressions/Interfaces/IImpressionsManager.cs
+++ b/src/Splitio/Services/Impressions/Interfaces/IImpressionsManager.cs
@@ -6,7 +6,7 @@ namespace Splitio.Services.Impressions.Interfaces
 {
     public interface IImpressionsManager
     {
-        KeyImpression Build(TreatmentResult treatmentResult, Key key);
+        KeyImpression Build(TreatmentResult treatmentResult, Key key, Dictionary<string, object> properties);
         void Track(List<KeyImpression> impressions);
         Task TrackAsync(List<KeyImpression> impressions);
     }
diff --git a/src/Splitio/Services/InputValidation/Interfaces/IEventPropertiesValidator.cs b/src/Splitio/Services/InputValidation/Interfaces/IPropertiesValidator.cs
similarity index 100%
rename from src/Splitio/Services/InputValidation/Interfaces/IEventPropertiesValidator.cs
rename to src/Splitio/Services/InputValidation/Interfaces/IPropertiesValidator.cs
diff --git a/tests/Splitio-tests/Unit Tests/Client/SplitClientAsyncTests.cs b/tests/Splitio-tests/Unit Tests/Client/SplitClientAsyncTests.cs
index d532bec5..8b342afe 100644
--- a/tests/Splitio-tests/Unit Tests/Client/SplitClientAsyncTests.cs	
+++ b/tests/Splitio-tests/Unit Tests/Client/SplitClientAsyncTests.cs	
@@ -72,7 +72,7 @@ public async Task GetTreatment_WhenNameDoesntExist_ReturnsControl()
             // Assert
             Assert.AreEqual("control", result);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
 
@@ -89,7 +89,7 @@ public async Task GetTreatment_WhenExist_ReturnsOn()
                 .ReturnsAsync(new List<TreatmentResult> { new TreatmentResult("feature_flag_test", Labels.DefaultRule, "on", false, 1000, null) });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -100,7 +100,7 @@ public async Task GetTreatment_WhenExist_ReturnsOn()
 
             _splitClient.Destroy();
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
         #endregion
@@ -123,7 +123,7 @@ public async Task GetTreatments_WithEmptyKey_ShouldReturnControl()
                 Assert.AreEqual("control", res.Value);
             }
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Never);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Never);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
 
@@ -184,7 +184,7 @@ public async Task GetTreatments_ShouldReturnTreatments()
                 });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             _blockUntilReadyService
@@ -201,7 +201,7 @@ public async Task GetTreatments_ShouldReturnTreatments()
             var resultOff = result[parsedSplitOff.name];
             Assert.AreEqual("off", resultOff);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Exactly(2));
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Exactly(2));
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -229,7 +229,7 @@ public async Task GetTreatments_WhenNameDoesntExist_ReturnsControl()
                 Assert.IsNull(res.Value.Config);
             }
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
@@ -278,7 +278,7 @@ public async Task GetTreatmentWithConfig_ShouldReturnOnWithConfig()
                 .ReturnsAsync(new List<TreatmentResult> { new TreatmentResult(feature, Labels.DefaultRule, treatmentExpected, false, null, configExpected) });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -288,7 +288,7 @@ public async Task GetTreatmentWithConfig_ShouldReturnOnWithConfig()
             Assert.AreEqual(treatmentExpected, result.Treatment);
             Assert.AreEqual(configExpected, result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -320,7 +320,7 @@ public async Task GetTreatmentWithConfig_WhenNotMach_ShouldReturnDefaultTreatmen
                 .ReturnsAsync(new List<TreatmentResult> { new TreatmentResult(feature, "label", defaultTreatment, false, null, configExpected) });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -330,7 +330,7 @@ public async Task GetTreatmentWithConfig_WhenNotMach_ShouldReturnDefaultTreatmen
             Assert.AreEqual(defaultTreatment, result.Treatment);
             Assert.AreEqual(configExpected, result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -357,7 +357,7 @@ public async Task GetTreatmentWithConfig_WhenConfigIsNull_ShouldReturnOn()
                 .Returns(true);
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -367,7 +367,7 @@ public async Task GetTreatmentWithConfig_WhenConfigIsNull_ShouldReturnOn()
             Assert.AreEqual(treatmentExpected, result.Treatment);
             Assert.IsNull(result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -399,7 +399,7 @@ public async Task GetTreatmentWithConfig_WhenIsKilled_ShouldReturnDefaultTreatme
                 .ReturnsAsync(new List<TreatmentResult> { new TreatmentResult(feature, "label", defaultTreatment, false, null, configExpected) });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -409,7 +409,7 @@ public async Task GetTreatmentWithConfig_WhenIsKilled_ShouldReturnDefaultTreatme
             Assert.AreEqual(defaultTreatment, result.Treatment);
             Assert.AreEqual(configExpected, result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -441,7 +441,7 @@ public async Task GetTreatmentWithConfig_WhenTrafficAllocationIsSmallerThanBucke
                 .ReturnsAsync(new List<TreatmentResult> { new TreatmentResult(feature, "label", defaultTreatment, false, config: configExpected) });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             // Act
@@ -451,7 +451,7 @@ public async Task GetTreatmentWithConfig_WhenTrafficAllocationIsSmallerThanBucke
             Assert.AreEqual(defaultTreatment, result.Treatment);
             Assert.AreEqual(configExpected, result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -567,7 +567,7 @@ public async Task GetTreatmentWithConfig_WhenNameDoesntExist_ReturnsControl()
             Assert.AreEqual("control", result.Treatment);
             Assert.IsNull(result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
@@ -591,7 +591,7 @@ public async Task GetTreatmentsWithConfig_WithEmptyKey_ShouldReturnControl()
                 Assert.IsNull(res.Value.Config);
             }
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Never);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Never);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
 
@@ -652,7 +652,7 @@ public async Task GetTreatmentsWithConfig_ShouldReturnTreatmentsWithConfigs()
                 });
 
             _impressionsManager
-                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()))
+                .Setup(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()))
                 .Returns(new KeyImpression());
 
             _blockUntilReadyService
@@ -671,7 +671,7 @@ public async Task GetTreatmentsWithConfig_ShouldReturnTreatmentsWithConfigs()
             Assert.AreEqual("off", resultOff.Treatment);
             Assert.AreEqual(configExpectedOff, resultOff.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Exactly(2));
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Exactly(2));
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
         }
 
@@ -699,7 +699,7 @@ public async Task GetTreatmentsWithConfig_WhenNameDoesntExist_ReturnsControl()
                 Assert.IsNull(res.Value.Config);
             }
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.TrackAsync(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
diff --git a/tests/Splitio-tests/Unit Tests/Client/SplitClientUnitTests.cs b/tests/Splitio-tests/Unit Tests/Client/SplitClientUnitTests.cs
index 56441467..f0c2cfb8 100644
--- a/tests/Splitio-tests/Unit Tests/Client/SplitClientUnitTests.cs	
+++ b/tests/Splitio-tests/Unit Tests/Client/SplitClientUnitTests.cs	
@@ -103,7 +103,7 @@ public void GetTreatment_WhenNameDoesntExist_ReturnsControl()
             // Assert
             Assert.AreEqual("control", result);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.Track(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
@@ -422,7 +422,7 @@ public void GetTreatmentWithConfig_WhenNameDoesntExist_ReturnsControl()
             Assert.AreEqual("control", result.Treatment);
             Assert.IsNull(result.Config);
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.Track(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
@@ -563,7 +563,7 @@ public void GetTreatmentsWithConfig_WhenNameDoesntExist_ReturnsControl()
                 Assert.IsNull(res.Value.Config);
             }
 
-            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>()), Times.Once);
+            _impressionsManager.Verify(mock => mock.Build(It.IsAny<TreatmentResult>(), It.IsAny<Key>(), It.IsAny<Dictionary<string, object>>()), Times.Once);
             _impressionsManager.Verify(mock => mock.Track(It.IsAny<List<KeyImpression>>()), Times.Never);
         }
         #endregion
diff --git a/tests/Splitio-tests/Unit Tests/Impressions/ImpressionsManagerTests.cs b/tests/Splitio-tests/Unit Tests/Impressions/ImpressionsManagerTests.cs
index 6f8521fa..f0d3b462 100644
--- a/tests/Splitio-tests/Unit Tests/Impressions/ImpressionsManagerTests.cs	
+++ b/tests/Splitio-tests/Unit Tests/Impressions/ImpressionsManagerTests.cs	
@@ -5,6 +5,7 @@
 using Splitio.Services.Cache.Interfaces;
 using Splitio.Services.Impressions.Classes;
 using Splitio.Services.Impressions.Interfaces;
+using Splitio.Services.InputValidation.Interfaces;
 using Splitio.Services.Tasks;
 using Splitio.Telemetry.Domain.Enums;
 using Splitio.Telemetry.Storages;
@@ -25,6 +26,7 @@ public class ImpressionsManagerTests
         private readonly Mock<ITelemetryRuntimeProducer> _telemetryRuntimeProducer;
         private readonly Mock<IUniqueKeysTracker> _uniqueKeysTracker;
         private readonly Mock<IStatusManager> _statusManager;
+        private readonly Mock<IPropertiesValidator> _propertiesValidator;
         private readonly ITasksManager _tasksManager;
 
         public ImpressionsManagerTests()
@@ -36,7 +38,15 @@ public ImpressionsManagerTests()
             _telemetryRuntimeProducer = new Mock<ITelemetryRuntimeProducer>();
             _uniqueKeysTracker = new Mock<IUniqueKeysTracker>();
             _statusManager = new Mock<IStatusManager>();
+            _propertiesValidator = new Mock<IPropertiesValidator>();
             _tasksManager = new TasksManager(_statusManager.Object);
+
+            _propertiesValidator
+                .Setup(mock => mock.IsValid(It.IsAny<Dictionary<string, object>>()))
+                .Returns(new PropertiesValidatorResult
+                {
+                    Success = false,
+                });
         }
 
         [TestMethod]
@@ -53,7 +63,7 @@ public void BuildImpressionWithOptimizedAndWithPreviousTime()
                 .Returns(ptTime);
 
             // Act.
-            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
 
             // Assert.
             Assert.AreEqual("matching-key", result.KeyName);
@@ -80,7 +90,7 @@ public void BuildImpressionWithDebugAndWithPreviousTime()
                 .Returns((long?)null);
 
             // Act.
-            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
 
             // Assert.
             Assert.AreEqual("matching-key", result.KeyName);
@@ -103,7 +113,7 @@ public void BuildImpressionWithDebugAndWithoutPreviousTime()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
 
             // Act.
-            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
 
             // Assert.
             Assert.AreEqual("matching-key", result.KeyName);
@@ -126,7 +136,7 @@ public void BuildAndTrack()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
 
             // Act.
-            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
             impressionsManager.Track(new List<KeyImpression> { imp });
            
             // Assert.
@@ -147,7 +157,7 @@ public void BuildAndTrackWithoutCustomerListener()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
 
             // Act.
-            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
             impressionsManager.Track(new List<KeyImpression> { imp });
 
             // Assert.
@@ -273,10 +283,10 @@ public void TrackWithoutCustomerListener_Optimized()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
             var impressions = new List<KeyImpression>
             {
-                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"))
+                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null)
             };
 
             var optimizedImpressions = impressions.Where(i => ImpressionsManager.ShouldQueueImpression(i)).ToList();
@@ -305,10 +315,10 @@ public void TrackWithoutCustomerListener_Debug()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
             var impressions = new List<KeyImpression>
             {
-                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"))
+                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null)
             };
 
             // Act.
@@ -332,7 +342,7 @@ public void BuildImpressionWithNoneMode()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
 
             // Act.
-            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var result = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
 
             // Assert.
             Assert.AreEqual("matching-key", result.KeyName);
@@ -355,7 +365,7 @@ public void BuildAndTrackWithNoneMode()
             var impTime = CurrentTimeHelper.CurrentTimeMillis();
 
             // Act.
-            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"));
+            var imp = impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null);
             impressionsManager.Track(new List<KeyImpression> { imp });
 
             // Assert.
@@ -374,10 +384,10 @@ public void TrackWithNoneMode()
 
             var impressions = new List<KeyImpression>
             {
-                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key")),
-                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"))
+                impressionsManager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null),
+                impressionsManager.Build(new TreatmentResult("feature-2", "label-2", "off", false, 432543, impTime: impTime), new Key("matching-key-2", "bucketing-key"), null)
             };
 
             // Act.
@@ -402,8 +412,8 @@ public async Task BuildAndTrackAsyncOptimized()
             // Act.
             await manager.TrackAsync(new List<KeyImpression>
             {
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"))
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null)
             });
 
             // Assert.
@@ -430,8 +440,8 @@ public async Task BuildAndTrackAsyncNone()
             // Act.
             await manager.TrackAsync(new List<KeyImpression>
             {
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"))
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null)
             });
 
             // Assert.
@@ -459,8 +469,8 @@ public async Task BuildAndTrackAsyncDebug()
             // Act.
             await manager.TrackAsync(new List<KeyImpression>
             {
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key")),
-                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"))
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null),
+                manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), null)
             });
 
             // Assert.
@@ -472,7 +482,89 @@ await manager.TrackAsync(new List<KeyImpression>
             _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsDeduped, 0), Times.Never);
         }
 
-        private ImpressionsManager GetManager(IImpressionListener impressionListener, ImpressionsMode mode = ImpressionsMode.Optimized, bool addPt = true, bool labelsEnabled = false, IImpressionsObserver impressionsObserver = null)
+        [TestMethod]
+        public async Task BuildAndTrackAsyncDebugdWithProperties()
+        {
+            // Arrange.
+            _propertiesValidator
+                .SetupSequence(mock => mock.IsValid(It.IsAny<Dictionary<string, object>>()))
+                .Returns(new PropertiesValidatorResult
+                {
+                    Success = true,
+                    Value = new Dictionary<string, object> { { "city", "mdp" } }
+                })
+                .Returns(new PropertiesValidatorResult
+                {
+                    Success = true,
+                    Value = new Dictionary<string, object>{ { "city", "tandil" } }
+                });
+
+            var manager = GetManager(_customerImpressionListener.Object, ImpressionsMode.Debug, addPt: true, labelsEnabled: true);
+            var impTime = CurrentTimeHelper.CurrentTimeMillis();
+
+            _impressionsObserver
+                .SetupSequence(mock => mock.TestAndSet(It.IsAny<KeyImpression>()))
+                .Returns((long?)null)
+                .Returns(100);
+
+            // Act.
+            var imp1 = manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), new Dictionary<string, object> { { "city", "mdp" } });
+            var imp2 = manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), new Dictionary<string, object> { { "city", "tandil" } });
+            await manager.TrackAsync(new List<KeyImpression>{ imp1, imp2 });
+
+            // Assert.
+            Assert.AreEqual("{\"city\":\"mdp\"}", imp1.Properties);
+            Assert.AreEqual("{\"city\":\"tandil\"}", imp2.Properties);
+            _impressionsCounter.Verify(mock => mock.Inc("feature", It.IsAny<long>()), Times.Never);
+            _impressionsObserver.Verify(mock => mock.TestAndSet(It.IsAny<KeyImpression>()), Times.Never);
+            _impressionsLog.Verify(mock => mock.LogAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsQueued, 2), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsDropped, 0), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsDeduped, 0), Times.Never);
+        }
+
+        [TestMethod]
+        public async Task BuildAndTrackAsyncOptimizedWithProperties()
+        {
+            // Arrange.
+            _propertiesValidator
+                .SetupSequence(mock => mock.IsValid(It.IsAny<Dictionary<string, object>>()))
+                .Returns(new PropertiesValidatorResult
+                {
+                    Success = true,
+                    Value = new Dictionary<string, object> { { "city", "mdp" } }
+                })
+                .Returns(new PropertiesValidatorResult
+                {
+                    Success = true,
+                    Value = new Dictionary<string, object>{ { "city", "tandil" } }
+                });
+
+            var manager = GetManager(_customerImpressionListener.Object, ImpressionsMode.Optimized, addPt: true, labelsEnabled: true);
+            var impTime = CurrentTimeHelper.CurrentTimeMillis();
+
+            _impressionsObserver
+                .SetupSequence(mock => mock.TestAndSet(It.IsAny<KeyImpression>()))
+                .Returns((long?)null)
+                .Returns(100);
+
+            // Act.
+            var imp1 = manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), new Dictionary<string, object> { { "city", "mdp" } });
+            var imp2 = manager.Build(new TreatmentResult("feature", "label", "off", false, 432543, impTime: impTime), new Key("matching-key", "bucketing-key"), new Dictionary<string, object> { { "city", "tandil" } });
+            await manager.TrackAsync(new List<KeyImpression>{ imp1, imp2 });
+
+            // Assert.
+            Assert.AreEqual("{\"city\":\"mdp\"}", imp1.Properties);
+            Assert.AreEqual("{\"city\":\"tandil\"}", imp2.Properties);
+            _impressionsCounter.Verify(mock => mock.Inc("feature", It.IsAny<long>()), Times.Never);
+            _impressionsObserver.Verify(mock => mock.TestAndSet(It.IsAny<KeyImpression>()), Times.Never);
+            _impressionsLog.Verify(mock => mock.LogAsync(It.IsAny<List<KeyImpression>>()), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsQueued, 2), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsDropped, 0), Times.Once);
+            _telemetryRuntimeProducer.Verify(mock => mock.RecordImpressionsStats(ImpressionsEnum.ImpressionsDeduped, 0), Times.Once);
+        }
+
+        private ImpressionsManager GetManager(IImpressionListener impressionListener, ImpressionsMode mode = ImpressionsMode.Optimized, bool addPt = true, bool labelsEnabled = false, IImpressionsObserver impressionsObserver = null, IPropertiesValidator propertiesValidator = null)
         {
             return new ImpressionsManager(_impressionsLog.Object,
                 impressionListener,
@@ -483,7 +575,8 @@ private ImpressionsManager GetManager(IImpressionListener impressionListener, Im
                 _tasksManager,
                 _uniqueKeysTracker.Object,
                 impressionsObserver ?? _impressionsObserver.Object,
-                labelsEnabled);
+                labelsEnabled,
+                propertiesValidator ?? _propertiesValidator.Object);
         }
     }
 }