# Fingerprinting users

Recognize returning browsers even when cookies are cleared. With **Collect browser fingerprint** enabled in your application's **Frontend** tab, the JavaScript tag computes a fingerprint hash from system and browser specifics, such as locales, GPU properties, and available fonts, and attaches it to the captured events.

## How it works

- The fingerprint is a stable hash like `v1_<hash>`, computed once per browser and cached locally.
- Every captured event carries the fingerprint, and the `session-start` event additionally includes the raw component data it was computed from.
- Because the fingerprint is derived from the browser itself rather than stored identifiers, it stays the same when the visitor removes cookies or uses a fresh session.

Use the fingerprint to correlate sessions coming from the same browser: filter or group events by the `fingerprint` field in [Events](https://rum.betterstack.com/team/0/explore-events ";_blank"), or query it over the [SQL API](https://betterstack.com/docs/rum/api/sql-api/).

## Privacy considerations

While perfectly legal, privacy-focused users might dislike fingerprint collection. Review it against your privacy policy and the regulations that apply to you.

To turn it off, disable **Collect browser fingerprint** in your application's **Frontend** tab. The change takes effect immediately, no redeploy needed.

## Prefer identified users where you can

Fingerprints recognize a browser, not a person. For signed-in traffic, [identify users](https://betterstack.com/docs/rum/identify-users/) instead: identification is exact, survives browser changes, and powers the [Users](https://rum.betterstack.com/team/0/users ";_blank") page.