301 Moved Permanently
3xx redirection
The resource has a new permanent URL; clients and search engines should use the Location instead.
301 says 'this moved for good — update your links'. Browsers follow the Location header and cache the redirect aggressively, often indefinitely, and search engines pass the old URL's ranking signals to the new one.
That permanence is the point, and also the trap: a mistaken 301 can stay stuck in visitors' browsers long after you remove it from the server.
| Class | 3xx Redirection |
|---|---|
| Retry? | Not applicable |
| Cacheable by default | Yes (heuristically, per RFC 9110) |
| Response body | Allowed |
| Defined in | RFC 9110 §15.4.2 — 301 Moved Permanently |
HTTP/1.1 301 Moved Permanently Location: https://www.example.com/new-path
When you'll see it
- Domain or URL structure changes: http → https, non-www → www,
/blog/post→/posts/post. - Normalising trailing slashes or letter case.
- Merging duplicate pages into one.
How to use it well
- Redirect each old URL to its closest new equivalent, not everything to the homepage — Google treats mass homepage redirects as soft 404s.
- Avoid chains (A → B → C); point every old URL straight at the final destination.
- Use 308 if the request might be a POST: clients may turn a redirected POST into a GET after a 301.
- Test with
curl -I— browser caches make 301 mistakes hard to see.
Useful here: 301 vs 302 vs 307 vs 308 · HTTP Status Checker · Fixing ERR_TOO_MANY_REDIRECTS
Send a 301 from your server
res.redirect(301, "https://www.example.com/new-path");
return NextResponse.redirect(new URL("https://www.example.com/new-path", request.url), 301);return redirect("https://www.example.com/new-path", code=301)http.Redirect(w, r, "https://www.example.com/new-path", http.StatusMovedPermanently)
return 301 https://www.example.com/new-path;
Check what a URL returns
Print just the status line from the command line, or check a whole list of URLs at once, with their response headers, in the HTTP Status Checker.
curl -sI https://example.com/your-path | head -n 1
Frequently asked questions
301 vs 302 — which should I use?
301 for permanent moves you want search engines to index at the new URL. 302 for temporary detours — maintenance, A/B tests — where the original URL should keep its place in search results.
301 vs 308?
Both are permanent. 308 forbids changing the method, so a POST stays a POST; 301 lets clients switch to GET, which browsers do. For page redirects 301 is fine; for APIs prefer 308.
How do I undo a 301 that browsers cached?
You can't clear visitors' caches. Redirect the new URL back, or serve content at the old one, and the stale redirects will fade as caches expire. Next time, test with a 302 and switch to 301 once you're sure.