Evercookie Test — persistent supercookies

"Alive" means the marker survived in that storage. Hit "reset" — and it is instantly respawned from the other storages: that is how evercookie works, which is why clearing cookies alone does not stop tracking. The marker is used only on this page and never sent to any external server.

What is a supercookie (evercookie)?

A normal cookie is easy to delete. An evercookie, or supercookie, hides copies of the same identifier across many browser storage mechanisms at once — localStorage, sessionStorage, IndexedDB, window.name, cache and more — so that deleting one restores it from the others. This test plants a marker across those vectors, then shows which ones survive after you clear your cookies, revealing how persistently you can be tracked.

FAQ

How do I delete supercookies?

Clearing “cookies” alone isn’t enough. Use your browser’s “clear site data” / “all storage” option for the site, which wipes localStorage, IndexedDB and cache together. Private/incognito windows discard all of it on close, and Tor Browser isolates and clears storage per session — the most reliable defence.

Are evercookies still used in 2026?

Aggressive full-storage evercookies are rarer now because browsers partition and auto-expire many storage types, but the underlying trick — stashing an ID in more than one place — still appears in tracking and anti-fraud scripts. Testing which vectors persist for you is the only way to know.

Is this the same as browser fingerprinting?

No, though they’re often combined. A supercookie stores an ID on your device and can be deleted if you find every copy. A fingerprint stores nothing — it recognises you from your device’s own characteristics. Trackers frequently use a fingerprint to rebuild a supercookie you cleared.

Does private mode stop supercookies?

Mostly. Incognito/private windows keep storage in memory and throw it away when you close every private window, so supercookies don’t persist between sessions. They can still track you within a single session, and they don’t hide your fingerprint or IP.

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What is a supercookie (evercookie)?

FAQ