diff --git a/VWO.xcworkspace/xcshareddata/swiftpm/Package.resolved b/VWO.xcworkspace/xcshareddata/swiftpm/Package.resolved
new file mode 100644
index 00000000..b448b27c
--- /dev/null
+++ b/VWO.xcworkspace/xcshareddata/swiftpm/Package.resolved
@@ -0,0 +1,32 @@
+{
+  "pins" : [
+    {
+      "identity" : "socket.io-client-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/socketio/socket.io-client-swift",
+      "state" : {
+        "revision" : "36db2ff0ebc7239187f9b382fd318e122da71caa",
+        "version" : "15.2.0"
+      }
+    },
+    {
+      "identity" : "starscream",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/daltoniam/Starscream",
+      "state" : {
+        "revision" : "e6b65c6d9077ea48b4a7bdda8994a1d3c6969c8d",
+        "version" : "3.1.1"
+      }
+    },
+    {
+      "identity" : "swift-nio-zlib-support",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-nio-zlib-support.git",
+      "state" : {
+        "revision" : "37760e9a52030bb9011972c5213c3350fa9d41fd",
+        "version" : "1.0.0"
+      }
+    }
+  ],
+  "version" : 2
+}
diff --git a/VWO/Models/VWOCampaign.h b/VWO/Models/VWOCampaign.h
index 8c37fbe4..1ed6445d 100644
--- a/VWO/Models/VWOCampaign.h
+++ b/VWO/Models/VWOCampaign.h
@@ -31,6 +31,7 @@ typedef NS_ENUM(NSInteger, CampaignStatus) {
 
 - (nullable instancetype)initWithDictionary:(NSDictionary *)campaignDict;
 - (nullable id)variationForKey:(NSString *)key;
+- (nullable id)testKey:(NSString *)testKey;
 - (nullable VWOGoal *)goalForIdentifier:(NSString *)identifier;
 
 @end
diff --git a/VWO/Models/VWOCampaign.m b/VWO/Models/VWOCampaign.m
index fc752819..adf9c8fb 100644
--- a/VWO/Models/VWOCampaign.m
+++ b/VWO/Models/VWOCampaign.m
@@ -81,6 +81,11 @@ - (nullable instancetype)initWithDictionary:(NSDictionary *) campaignDict {
     return self;
 }
 
+- (nullable id)testKey:(NSString *)testKey {
+    NSParameterAssert(testKey);
+    //If key does not exist then NSDictionary returns nil
+    return self.testKey;
+}
 - (nullable id)variationForKey:(NSString *)key {
     NSParameterAssert(key);
     //If key does not exist then NSDictionary returns nil
diff --git a/VWO/VWO.h b/VWO/VWO.h
index fdf96392..ab8b32d5 100644
--- a/VWO/VWO.h
+++ b/VWO/VWO.h
@@ -143,6 +143,20 @@ __deprecated_msg("Use objectForKey:defaultValue instead");
  */
 + (BOOL)boolForKey:(NSString *)key defaultValue:(BOOL)defaultValue NS_SWIFT_NAME(boolFor(key:defaultValue:));
 
+/**
+ Fetch variation for given key
+
+ @param key key whose value is to be fetched
+
+ @param defaultValue Value that is to be returned if key is not found
+ 
+ @param testKey Value  is Test key which is used with the variation Key
+
+ @return variation if available else `defaultValue`
+ */
++ (BOOL)boolForKey:(NSString *)key defaultValue:(BOOL)defaultValue testKey:(NSString *)testKey NS_SWIFT_NAME(boolFor(key:defaultValue:testKey:));
+
+
 /**
  Fetch variation for given key
 
@@ -154,6 +168,19 @@ __deprecated_msg("Use objectForKey:defaultValue instead");
  */
 + (int)intForKey:(NSString *)key defaultValue:(int)defaultValue NS_SWIFT_NAME(intFor(key:defaultValue:));
 
+/**
+ Fetch variation for given key
+
+ @param key key whose value is to be fetched
+
+ @param defaultValue Value that is to be returned if key is not found
+ 
+ @param testKey Value  is Test key which is used with the variation Key
+
+ @return variation if available else `defaultValue`
+ */
++ (int)intForKey:(NSString *)key defaultValue:(int)defaultValue testKey:(NSString *)testKey NS_SWIFT_NAME(intFor(key:defaultValue:testKey:));
+
 /**
  Fetch variation for given key
 
@@ -165,6 +192,19 @@ __deprecated_msg("Use objectForKey:defaultValue instead");
  */
 + (double)doubleForKey:(NSString *)key defaultValue:(double)defaultValue NS_SWIFT_NAME(doubleFor(key:defaultValue:));
 
+/**
+ Fetch variation for given key
+
+ @param key key whose value is to be fetched
+
+ @param defaultValue Value that is to be returned if key is not found
+ 
+ @param testKey Value  is Test key which is used with the variation Key
+
+ @return variation if available else `defaultValue`
+ */
++ (double)doubleForKey:(NSString *)key defaultValue:(double)defaultValue testKey:(NSString *)testKey NS_SWIFT_NAME(doubleFor(key:defaultValue:testKey:));
+
 /**
  Fetch variation for given key
 
@@ -176,6 +216,19 @@ __deprecated_msg("Use objectForKey:defaultValue instead");
  */
 + (nullable NSString *)stringForKey:(NSString *)key defaultValue:(nullable NSString *)defaultValue NS_SWIFT_NAME(stringFor(key:defaultValue:));
 
+/**
+ Fetch variation for given key
+
+ @param key key whose value is to be fetched
+
+ @param defaultValue Value that is to be returned if key is not found
+ 
+ @param testKey Value  is Test key which is used with the variation Key
+
+ @return variation if available else `defaultValue`
+ */
++ (nullable NSString *)stringForKey:(NSString *)key defaultValue:(nullable NSString *)defaultValue testKey:(NSString *)testKey NS_SWIFT_NAME(stringFor(key:defaultValue:testKey:));
+
 
 /**
  Fetch variation name for given campaign.
diff --git a/VWO/VWO.m b/VWO/VWO.m
index fccec85b..d82154c3 100644
--- a/VWO/VWO.m
+++ b/VWO/VWO.m
@@ -110,20 +110,33 @@ + (void)launchSynchronouslyForAPIKey:(NSString *)apiKey
     });
 }
 
-+ (id)objectForKey:(NSString *)key {
++ (id)objectForKey:(NSString *)key{
     NSParameterAssert(key);
     __block id object;
     dispatch_barrier_sync(VWOController.taskQueue, ^{
-        object = [VWOController.shared variationForKey:key];;
+        object = [VWOController.shared variationForKey:key];
     });
     return object;
 }
 
-+ (id)objectForKey:(NSString *)key defaultValue:(nullable id)defaultValue {
++ (id)objectForKey:(NSString *)key testKey:(NSString *)testKey{
+    NSParameterAssert(key);
+    __block id object;
+    dispatch_barrier_sync(VWOController.taskQueue, ^{
+        object = [VWOController.shared variationForKey:key testKey:testKey];
+    });
+    return object;
+}
++ (id)objectForKey:(NSString *)key defaultValue:(nullable id)defaultValue{
     id object = [self objectForKey:key];
     return object != nil ? object : defaultValue;
 }
 
++ (id)objectForKey:(NSString *)key defaultValue:(nullable id)defaultValue testKey:(NSString *)testKey{
+    id object = [self objectForKey:key testKey:testKey];
+    return object != nil ? object : defaultValue;
+}
+
 + (id)variationForKey:(NSString *)key defaultValue:(id)defaultValue {
         // Deprecated
     return [self objectForKey:key defaultValue:defaultValue];
@@ -134,22 +147,43 @@ + (BOOL)boolForKey:(NSString *)key defaultValue:(BOOL)defaultValue {
     return object != nil ? [object boolValue] : defaultValue;
 }
 
++ (BOOL)boolForKey:(NSString *)key defaultValue:(BOOL)defaultValue testKey:(NSString *)testKey{
+    id object = [self objectForKey:key testKey:testKey];
+    return object != nil ? [object boolValue] : defaultValue;
+}
+
 + (int)intForKey:(NSString *)key defaultValue:(int)defaultValue {
     id object = [self objectForKey:key];
     return object != nil ? [object intValue] : defaultValue;
 }
 
++ (int)intForKey:(NSString *)key defaultValue:(int)defaultValue testKey:(NSString *)testKey{
+    id object = [self objectForKey:key testKey:testKey];
+    return object != nil ? [object intValue] : defaultValue;
+}
+
 + (double)doubleForKey:(NSString *)key defaultValue:(double)defaultValue {
     id object = [self objectForKey:key];
     return object != nil ? [object doubleValue] : defaultValue;
 }
 
++ (double)doubleForKey:(NSString *)key defaultValue:(double)defaultValue testKey:(NSString *)testKey{
+    id object = [self objectForKey:key testKey:testKey];
+    return object != nil ? [object doubleValue] : defaultValue;
+}
+
 + (NSString *)stringForKey:(NSString *)key defaultValue:(NSString *)defaultValue {
     NSParameterAssert(key);
     id object = [self objectForKey:key];
     return [NSString stringWithFormat:@"%@", object != nil ? object : defaultValue];
 }
 
++ (NSString *)stringForKey:(NSString *)key defaultValue:(NSString *)defaultValue testKey:(NSString *)testKey{
+    NSParameterAssert(key);
+    id object = [self objectForKey:key testKey:testKey];
+    return [NSString stringWithFormat:@"%@", object != nil ? object : defaultValue];
+}
+
 + (nullable NSString *)variationNameForTestKey:(NSString *)campaignTestKey {
     NSParameterAssert(campaignTestKey);
     __block NSString *variationName;
diff --git a/VWO/VWOController.h b/VWO/VWOController.h
index c6c525f2..7bdae432 100644
--- a/VWO/VWOController.h
+++ b/VWO/VWOController.h
@@ -37,6 +37,7 @@ static NSString *kVWOSDKversion = @"2.10.0";
 
 - (void)trackConversion:(NSString *)goal withValue:(nullable NSNumber *)value;
 - (nullable id)variationForKey:(NSString *)key;
+- (nullable id)variationForKey:(NSString *)key testKey:(NSString *)testKey;
 - (nullable NSString *)variationNameForCampaignTestKey:(NSString *)campaignTestKey;
 - (void)pushCustomDimension:(NSString *) customDimensionKey withCustomDimensionValue:(NSString *) customDimensionValue;
 
diff --git a/VWO/VWOController.m b/VWO/VWOController.m
index ad83a370..7675bdb6 100644
--- a/VWO/VWOController.m
+++ b/VWO/VWOController.m
@@ -266,6 +266,52 @@ - (id)variationForKey:(NSString *)key {
     return finalVariation;
 }
 
+- (id)variationForKey:(NSString *)key testKey:(NSString *)testKey{
+    if (!_initialised) {
+        VWOLogWarning(@"variationForKey(%@) called before launching VWO", key);
+        return nil;
+    }
+
+    if (VWOSocketConnector.isConnectedToBrowser) {
+        if(key && _previewInfo != nil) {
+            VWOLogInfo(@"Socket: got variation %@ for key %@", _previewInfo[key], key);
+            return _previewInfo[key];
+        }
+        VWOLogInfo(@"Socket: got variation nil for key %@", key);
+        return nil;
+    }
+
+    id finalVariation = nil;
+    for (VWOCampaign *campaign in _campaignList) {
+        id variation = [campaign variationForKey:key];
+        
+        BOOL isCampaignTracked = [VWOUserDefaults isTrackingUserForCampaign:campaign];
+
+        id campaginTestKey = [campaign testKey:testKey];
+        if(campaginTestKey){
+            NSString * campTestKey = campaginTestKey;
+            //If variation Key is present in Campaign and testKey matches
+            if (variation && [campTestKey isEqualToString:testKey]) {
+                if (isCampaignTracked) {
+                    finalVariation = variation;
+                } else {
+                    VWOSegmentEvaluator *evaluator = [VWOSegmentEvaluator makeEvaluator:_customVariables];
+                    BOOL canBePart = [evaluator canUserBePartOfCampaignForSegment:campaign.segmentObject];
+                    if (canBePart) {
+                        finalVariation = variation;
+                        [self trackUserForCampaign:campaign];
+                    }
+                }
+            }
+        }
+    }
+    if (finalVariation == [NSNull null]) {
+        // finalVariation can be NSNull if Control is assigned to campaign
+        return nil;
+    }
+    VWOLogDebug(@"Got variation %@ for key %@", finalVariation, key);
+    return finalVariation;
+}
 - (nullable NSString *)variationNameForCampaignTestKey:(NSString *)campaignTestKey {
     if (!_initialised) {
         VWOLogWarning(@"variationNameForCampaignTestKey(%@) called before launching VWO", campaignTestKey);
diff --git a/VWO/VWOURL.m b/VWO/VWOURL.m
index d3a8638f..ac45d101 100644
--- a/VWO/VWOURL.m
+++ b/VWO/VWOURL.m
@@ -109,7 +109,7 @@ - (NSURL *)forMakingUserPartOfCampaign:(VWOCampaign *)campaign
       @"u"            : VWOUserDefaults.UUID,
       @"s"            : [NSString stringWithFormat:@"%lu", (unsigned long)VWOUserDefaults.sessionCount],
       @"random"       : [self randomNumber],
-      @"sId"          : [NSString stringWithFormat:@"%f", date.timeIntervalSince1970],
+       @"sId"          : [NSString stringWithFormat:@"%lu", (unsigned long)date.timeIntervalSince1970],
       @"ed"           : [self extraParametersWithDate:date].toString
       } mutableCopy];
     if (config.customDimension != nil) {