It depends on your purpose.

301 says “this isn t the proper URL, look elsewhere and use remember that other URL is better; don t come back here!”.

302 says “this is the proper URL which you should carry on using, but to actually get the content look elsewhere”.

303 is like 302 but specifically for redirections after a form submission.

If your purpose is a URL shortener then 303 isn t really relevant. It ll still work, but offers nothing over the normal 302. For a URL shortener I d say 301 would be most suitable, as the other URL is the ‘real’ one. Saying 302 is trying to keep the ownership of the address and any SEO momentum caused by its use for yourself: a bit rude, but maybe you want to be rude.

Different status codes have different meanings. The HTTP specification describes them: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

301 — moved permanently (and change an

302 — found here

303 — find your response here, but use GET even if you started out with POST

If we take, for example, an Atom feed that has the URL changed for some reason (perhaps it is being moved to Amazon S3 or something). Given a 301 result, the feed reader should note that the feed has moved and update it s subscription. Given a 302, it will get the feed from its new location, but hit the original server looking for the original URI every time it checks for an update. (And a 303 would be silly in this situation).

Read http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html for the answer.

10.3.2 301 Moved Permanently

The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs. Clients with link editing capabilities ought to automatically re-link references to the Request-URI to one or more of the new references returned by the server, where possible. This response is cacheable unless indicated otherwise.

10.3.3 302 Found

The requested resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client SHOULD continue to use the Request-URI for future requests. This response is only cacheable if indicated by a Cache-Control or Expires header field.

Have a look at the HTTP 1.1 Status Code definitions. Different status codes imply different meanings and, therefore, encourage different behavior. Try to use the code which best matches your use case.

301 is for a permanent redirect and if this is what you want to do then this is recommended by all SEO experts.

"A 301 redirect is a permanent redirect that passes full link equity (ranking power) to the redirected page. 301 refers to the HTTP status code for this type of redirect. In most instances, the 301 redirect is the best method for implementing redirects on a website." https://moz.com/learn/seo/redirection#:~:text=A%20301%20redirect%20is%20a,implementing%20redirects%20on%20a%20website.