304 Not Modified
The cached copy is still good, so there is no body. The reply to a conditional request with If-None-Match or If-Modified-Since.
What to do
Nothing is wrong. The client asked with If-None-Match or If-Modified-Since, its cached copy is still good, and it uses that. A 304 has no body.
- Class
- 3xx Redirection. The client has to take another step to complete the request.
- Registered
- Yes, in the IANA HTTP status code registry.
- Cacheable by default
- No. A cache stores it only when Cache-Control or Expires says to.
- References
- RFC 9110 ยง15.4.5 · MDN
Example response
HTTP/1.1 304 Not Modified ETag: "33a64df5" Cache-Control: max-age=3600