Request
If-None-Match
Makes the request conditional based on an ETag value; enables efficient cache validation.
Syntax
If-None-Match: "<etag_value>"Example
If-None-Match: "33a64df551425fcc55e4d42a148795d9f25f89d4"Description
The If-None-Match header makes a GET or HEAD request conditional. The client sends the ETag value from a previous response; if the resource has not changed, the server returns 304 Not Modified instead of the full response body.
This is the primary mechanism for cache validation with ETags and reduces bandwidth by avoiding redundant data transfer.
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