What is the difference between different HTTP status codes (301 vs 302 vs 307 vs 308)?
I'm working on building a web app and I'm a bit confused about the differences between HTTP status codes related to redirects, specifically 301, 302, 307, and 308.
From what I understand, 301 and 302 are common older codes, but I keep seeing 307 and 308 in documentation. What exactly is the difference between these four codes, what's their semantic meaning, and when should each be used (and/or not used)?
Historically many clients changed POST requests to a GET when following 301 or 302 redirects. For this reason, the more modern 307 and 308 redirect status codes were created to ensure that the request method is preserved by the client when following the redirect.
Permanent Redirects
These redirect codes indicate that the requested resource has permanently moved to a new URL. Browsers may cache these redirects much more aggressively than temporary redirects and you should use them when you don't expect the redirect location to change, or for the page to return content itself in the near future.
301- Moved Permanently: Historically, clients changed a POST to a GET when following a301, although this was not required by the original spec.308- Permanent Redirect:308serves the same purpose as301, but guarantees the client will never change request method automatically (POST stays POST).
Temporary Redirects
On the other hand, these redirect codes indicate that the requested resource is temporarily at a different URL. Browsers do not cache these redirects the same as permanent (301/308) redirects, and you should use them when you expect the redirect location to change often, or for the page to return content itself at some point** in the future.
302- Found: Originally meant to preserve the HTTP method, but in practice most browsers, similar to301, changed POST to GET.307- Temporary Redirect: Serves the same purpose as302, but never changes request method automatically.
Overall, you should generally prefer 307 and 308 for new applications, and use 301 and 302 mainly for compatibility with older clients or in rare/specific use cases.
