Success and redirects

Success responses live in the 2xx range. Redirects and cache checks live in 3xx. Both are normal outcomes, not errors.

Common 2xx codes:

• 200 OK: general success with a body.
• 201 Created: a new resource now exists (typical after POST).
• 204 No Content: success, but no body to return (common after DELETE).

3xx responses usually include a Location header telling the client where to go next:

HTTP/1.1 301 Moved Permanently
Location: https://flaviocopes.com/download/

301 and 308 mean permanent moves. Search engines and bookmarks should update to the new URL. 302 and 307 mean temporary moves.

There is a subtle method rule. 307 and 308 require the client to repeat the same method at the new URL. Old client behavior around 301 and 302 sometimes turned a POST into a GET on the redirect target. For form submissions that must stay POST, prefer 307 or 308.

304 Not Modified is a 3xx code, but it is not a redirect. The client asked “do I still have the latest copy?” and the server answered “yes, use your cache.” No body travels in that case.

Watch a redirect chain:

curl -I -L https://flaviocopes.com/books

You may see a 301 with Location: /download/, then a 200 on the final URL after curl follows -L.

Compare with a cached validation request in DevTools: a 304 row often has a tiny response size because the browser reused stored bytes.

My advice: pick permanent vs temporary deliberately when you configure redirects in your host or framework. Permanent codes consolidate SEO signals; temporary codes tell clients not to rewrite bookmarks yet.

Try this on your own project: list every redirect your site emits and mark each as permanent or temporary. Check whether any POST route redirects with a code that might change the method.