If-None-Match

Sends a stored ETag back: the server answers 304 Not Modified if nothing changed.

Header name, or pasted headers

Explained

Examples

Example

If-None-Match: "33a64df551425fcc55e4d42a148795d9f25f89d4"

Browsers add it themselves from their cache. It only helps if the server compares tags and sends 304.

Defined in RFC 9110 §13.1.2.