HTTP status codes / 3xx — Redirection
304 Not Modified
What it means
The client's cached copy is still valid — the server sends no body, saving bandwidth. The response to a conditional request (If-None-Match / If-Modified-Since).
What causes it
Normal, healthy HTTP caching at work.
How to fix it
Seeing stale content with 304s? The ETag/Last-Modified on the server is not changing when it should — fix cache validation, not the client.