HTTP 3xx
304 Not Modified
The cached copy is still valid, so the server returned no body to save bandwidth.
What causes it
- A conditional request matched an ETag or Last-Modified value.
How to fix it
Expected caching behavior. No action needed.
Example response
A typical raw HTTP response a client receives for a 304, with the headers this code is defined around.
HTTP/1.1 304 Not Modified
ETag: "3f80f-1b6-3e1cb03b"Related codes
300
Multiple ChoicesThe request has more than one possible response and the client should choose one.303
See OtherThe response is at another URL and should be retrieved with a GET, regardless of the original method.301Common
Moved PermanentlyThe resource has permanently moved to a new URL. Browsers and search engines should update to the new location.302Common
FoundThe resource is temporarily at a different URL. Unlike a 301, clients keep using the original URL for future requests.307
Temporary RedirectLike a 302, but the request method and body must not change on the redirected request.308
Permanent RedirectLike a 301, but the request method and body must not change.Know before your visitors do.
Sentinel checks your site around the clock from multiple regions and alerts you the moment it starts returning a 3xx error, so you can fix it before it costs you.