301 redirect

A 301 is the HTTP status code 301 Moved Permanently. The server answers a request with that code and a Location header, and the client goes to the address in the header. The word that matters is permanent: the response is cacheable by default, so a browser or an intermediate cache may remember it and send the visitor onward on later clicks without ever asking the server again. Search engines read it the same way and pass the ranking signals of the old address to the new one, which is why a 301 is the correct answer when a page really has moved.

For short links the same property is a trap. A cached redirect is a click your platform never sees, so counts drift low, and a destination changed later does not reach anyone whose browser still holds the old answer. Rotation, splits and targeting stop working for those visitors entirely. Link platforms therefore answer with a temporary code and reserve 301 for cases where the address is genuinely retired and the statistics no longer matter.