// supercookies
what is ETag / cache-based cookie?
The server hands each visitor a unique ETag (or Last-Modified) on a cached asset; the browser replays it in the next If-None-Match request, so the validator IS the identifier, with no cookie in sight.. Fast-decaying: browser mitigations land release-to-release; asOf 2026-06-15. Distilled from the richards supercookies catalog.
source capture as of 2026-06-15
in the benchmark
ETag / cache-based cookie is tracked as part of the supercookies taxonomy. see how tracked tools score against it on the capability matrix.