HTTP 304 Not Modified

The request condition indicates that the client can reuse its stored representation without receiving a response body.

Use 304 for a conditional GET or HEAD with ETag or Last-Modified validation when the client can reuse its stored body.

httpstatus codecacheconditional

Response (http)

HTTP/1.1 304 Not Modified

Use 304 for a conditional GET or HEAD with ETag or Last-Modified validation when the client can reuse its stored body.

Common mistakes

Sending a body with 304 or headers that contradict the stored representation it is supposed to validate.

Registry reference: RFC9110, Section 15.4.5

Sources