The Get Variation Name API allows you to retrieve the variation assigned to a user for a specific Full Stack A/B experiment without re-evaluating or re-activating the experiment.

This is useful when you want to:

• Fetch the already assigned variation

• Apply variation-specific logic at a later point in the user flow

• Ensure consistency across multiple screens or actions
  

What this allows you to do  

Using this API, you can:

• Retrieve the variation already assigned to a user

• Avoid duplicate experiment activation calls

• Apply consistent behavior across different parts of your app

• Safely handle users who are not part of the experiment

When to use Get Variation Name  

You should use this API when:

• The experiment has already been activated for the user

• You want to check the assigned variation again

• You need variation information outside the initial activation flow

If the experiment has not been activated earlier, this API may return null.

Get variation name with user attributes  

User attributes can be passed when retrieving the variation name to ensure audience conditions are evaluated correctly.

KOTLIN

1. // Create a map to hold user attributes
2. val userAttributes = mutableMapOf(
3. "DeviceType" to "Phone",
4. "OS" to "Android",
5. "OSVersion" to "14",
6. "DeviceModel" to "Pixel 8 Pro"
7. )
8. // Get the variation name for the user
9. val variationName = pageSenseClient.getVariationName(
10. experimentName,
11. userId,
12. userAttributes
13. )
14. // Handle variation-specific logic
15. if (variationName == "Original") {
16. // Handle Original variation
17. } else if (variationName == "Variation 1") {
18. // Handle Variation 1
19. } else if (variationName == "Variation 2") {
20. // Handle Variation 2
21. } else if (variationName == "Variation 3") {
22. // Handle Variation 3
23. } else {
24. // User is not part of the experiment
    }

JAVA

1. import java.util.HashMap;
2. // Create a map to hold user attributes
3. HashMap<String, String> userAttributes = new HashMap<>();
4. userAttributes.put("DeviceType", "Phone");
5. userAttributes.put("OS", "Android");
6. userAttributes.put("OSVersion", "14");
7. userAttributes.put("DeviceModel", "Pixel 8 Pro");
8. // Get the variation name for the user
9. String variationName = pageSenseClient.getVariationName(
10. experimentName,
11. userId,
12. userAttributes
13. );
14. // Handle variation-specific logic
15. if ("Original".equals(variationName)) {
16. // Handle Original variation
17. } else if ("Variation 1".equals(variationName)) {
18. // Handle Variation 1
19. } else if ("Variation 2".equals(variationName)) {
20. // Handle Variation 2
21. } else if ("Variation 3".equals(variationName)) {
22. // Handle Variation 3
23. } else {
24. // User is not part of the experiment
25. }

When To Use activateExperiment() vs getVariationName()

Get variation name without user attributes  

If no user attributes are available, you can retrieve the variation using only the experiment name and user ID.
Only experiments targeting All Visitors will qualify in this case.

1. // Get the variation name without user attributes
2. val variationName = pageSenseClient.getVariationName(
3. experimentName,
4. userId
5. )

How the API Works    

When activateExperiment() method is invoked, it follows a series of steps to determine whether a variation should be assigned to the user:

1. Audience Targeting

• If the user’s attributes match the audience targeting conditions, the evaluation proceeds.

• If they don’t match, the API immediately returns null, indicating the user is not eligible for the experiment.
  
  

2. User Storage Service

• If a stored variation already exists for the given user Id for the experiment, it is retrieved from the storage and returned.

• If not, the SDK proceeds to assign a new variation via hashing algorithm.
  
  

3. Hashing with MurmurHash

This hash value determines the user’s position in the experiment’s traffic allocation range and assign a variation.

• MurmurHash always generates the same hash value for a given user  ID and  the experiment key combination.

• This ensures that users always receive a consistent variation assignment across different sessions and browsers.

4. Variation Mapping

 These ranges are non-overlapping and collectively cover the experiment’s total traffic allocation.

• If the user’s hash value falls within a particular variation’s range, that variation will be allocated to the user.

• If the user’s hash value falls outside all assigned ranges for the variations, no variation will be assigned to the user and the user will not qualify for the experiment, and NULL will be returned for the variation.
  

5. Tracking and Analytics

6. Return Value  

Important notes  

• This API does not activate an experiment

• It only returns the variation already assigned to the user

• If the user does not qualify or the experiment was never activated, null is returned

• Always handle the null case safely

Best practices  

• Activate the experiment once per user session

• Use getVariationName for subsequent checks

• Use a stable user identifier for consistent results

• Pass user attributes only when available