clusterUUID

clusterUUID (string): A unique or semi-unique identifier representing a browser or device, allowing tracking of user sessions.

While designed to remain consistent across sessions, multiple devices or users with similar configurations may share the same clusterUUID. It’s best used as a probabilistic identifier rather than an absolute one.

Note: If an API key is not supplied and the user has opted out of tracking via Global Privacy Control (GPC), the clusterUUID will be set to user-opt-out.