What is a visitor ID?

A visitor ID is a random, anonymous identifier that a recording SDK generates on first contact and stores on the device, so later sessions from the same browser or app can be grouped together without any personal data.

Why it matters

Sessions are short; people come back. A visitor ID is what lets a reviewer see that the session where a user gave up on Tuesday and the one where they succeeded on Thursday belong to the same person, without knowing anything about who that person is.

It is also what makes a sampling rate behave. A sampling decision keyed on the visitor ID means a recorded person stays recorded, and an unrecorded one is never half-recorded. Until you call identify, the visitor ID is the only identity a recording has.

How AnyReplay handles it

The AnyReplay web SDK generates a visitor ID and stores it in the browser; the sampling decision is made once per visitor and remembered, so a recorded person stays recorded across pages and later visits. The React Native SDK has no persistent storage of its own: pass an AsyncStorage instance through the storage option so it can recognise a returning visitor, or leave it out and every launch is a new visitor. A visitor ID carries no PII until you attach some, and the sessions it groups expire under your data retention policy.