User Pseudo ID

A user pseudo ID is an anonymous identifier that, instead of a real identity, recognizes a device or browser over time so scattered visits can be tied to one user.

A user pseudo ID is the backbone of counting how many people in privacy-first analytics: without it every visit is a stranger and the concept of a returning user is impossible, yet being anonymous it exposes no personal information. The pseudo part matters; this identifier does not know the real user, only a browser on a device, and that boundary creates two perennial errors: one person on a phone and a laptop has two pseudo IDs and so counts as two users, and if the user clears cookies or opens a private window they get a fresh ID and appear as a new user. So the user count is always an estimate that runs high, not an exact census of people. Tying several pseudo IDs to one real person — called identity resolution — requires a login or extra data and does not come from the anonymous identifier itself.