Moved Permanently

Overview

301 Moved Permanently announces that a resource has permanently moved to a new URL, given in the Location header. Browsers and search engines treat it as a permanent move, sending future requests to the new URL and transferring link equity (ranking, reputation) to it.

For SEO it is the standard tool for domain migrations, HTTP→HTTPS switches, and URL restructuring; the longer it stays in place, the more reliably search indexes update to the new URL.

When it happens

• Use it when a page or site has permanently moved to a new URL or domain, to steer all future requests to the new location.
• Return it when forcing HTTP to HTTPS, canonicalizing non-www to www (or vice versa), or permanently changing a URL structure or slug.

Request / Response example

GET /old-page HTTP/1.1
Host: example.com

HTTP/1.1 301 Moved Permanently
Location: https://example.com/new-page
Content-Type: text/html

<h1>Moved Permanently</h1><p>The document has moved <a href="/new-page">here</a>.</p>

In code

location = /old-page {
    return 301 /new-page;
}
# force https + non-www
server { return 301 https://example.com$request_uri; }

app.get('/old-page', (req, res) => {
  res.redirect(301, '/new-page');
});

Notes

• In practice: update clients and internal/external links to point at the new URL in Location, and keep the 301 in place for a long time (ideally permanently) so link equity fully transfers.
• Browsers cache 301 aggressively, so a misconfigured 301 is hard to undo because of caching — test with 302 before committing.
• Historically some browsers changed POST to GET on a 301 redirect, so use 308 instead of 301 when the request method must be preserved.
• To help search engines re-index the new URL, keep redirect chains short and update your sitemap to the new URLs.

Related status codes

Related headers

Specification