What does HTTP 304 mean?
The cached copy of the resource is still valid so no body is sent.
Common causes and when you see it
Returned when a conditional request (If-None-Match or If-Modified-Since) matches.
How to fix or handle it
Make sure ETag and Last-Modified are stable so caching works.
Test it yourself
Send a request with the online API tester, inspect the response with the HTTP header checker, or host an endpoint that returns 304 with the mock API generator to see how your app reacts.
HTTP 304 questions
The cached copy of the resource is still valid so no body is sent.
Returned when a conditional request (If-None-Match or If-Modified-Since) matches.
Make sure ETag and Last-Modified are stable so caching works.