Identifying Users (User ID)

User Identifier, also abbreviated as User ID, is a way to identify a user uniquely. Since campaigns are directly associated with users, our SDK relies on the User ID you must provide us. User ID is simply a string. You can customize the User ID based on your business requirements.

You can use a client-side first-party cookie, which will be available when any request to your server is made or device ID, or use a universal user identifier (UUID) to identify each user. But make sure, if you want consistent behaviour for a user, the same User ID should be provided each time. For example, a user comes on the website for the first time, and you assign a User ID as f34c3d91-a66e-4389-92fb-595fa9874725 to that user. Using our SDK, let's assume the user got Variation-1. Now, if the same user comes back, then our SDK assumes the same User ID for consistent behaviour.

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User IDs should be Unique

Ensure User IDs are unique: User IDs must be unique for a campaign. VWO SDK relies on the User ID you provide for consistent behavior across platforms. VWO buckets users and provides test metrics based on the User IDs that you provide.

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Anonymization of User ID

The User IDs you provide are anonymized by our SDKs into a UUID before being sent to VWO servers.