ETag

A version fingerprint that lets clients skip downloading unchanged data.

What is ETag?

An ETag is a version fingerprint of a response. Clients send it back with If-None-Match; if nothing changed, the server answers 304 Not Modified with no body.

ETag: "v7-a1b2c3"

GET /recipes/42
If-None-Match: "v7-a1b2c3"
→ 304 Not Modified

Level: Freelancer · More Web Development terms at this level

Updated September 27, 2026