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.

Tracking Modes

Responses that field clusterUUID can be configured in three different ways: basic, standard, or advanced. Each provides increasing levels of uniqueness, resulting in a higher chance that clusterUUID will be unique to a single user.

Basic

Unlike the other settings, basic does not take third-party network data into account when determining a clusterUUID. This setting will result in the highest number of users being grouped within a single clusterUUID.

Standard

standard requests utilize third-party IP intelligence data, including country, ISP, and anonymity indicators (such as VPN or datacenter usage), when determining the clusterUUID. This significantly increases the number of unique users that can be tracked compared to basic requests.

Advanced

advanced requests use Maxmind IP intelligence data and will result in the highest levels of uniqueness and accuracy. Maxmind's data allows us to more effectively track users using consumer privacy networks such as iCloud Private Relay, as well as cut down on false matches.