301 Moved Permanently

What it means

A permanent URL change, and the only redirect that reliably passes SEO authority. Be certain: browsers cache 301s aggressively and for a long time, so a mistaken 301 can be effectively irreversible for returning visitors. Historically it also rewrites POST to GET.

Class

3xx Redirection

Defined in

RFC 9110 §15.4.2

Cached by default

Yes, without explicit headers

When you receive a 301

• Follow the Location header - browsers and most HTTP clients do it automatically.
• Update links, bookmarks and configuration: the old URL is not coming back.
• If a POST became a GET after the redirect, that is 301's historical behaviour; the server should be sending 308.

When you send a 301

• Use it for a permanent move - a new domain, a restructured path. Search engines transfer the old URL's ranking to the new one.
• Browsers cache a 301, sometimes for as long as the cache lives. Try a 302 first if you are not certain the move is final.
• For an API that receives POST or PUT, send 308 so the method survives the redirect.

On the wire

HTTP/1.1 301 Moved Permanently
Location: https://revquix.com/tools/json-formatter
Content-Length: 0

Often confused with

• 308 Permanent RedirectPermanently elsewhere, and the method must not change.
• 302 FoundThe resource is temporarily at a different URL.