In more detail
"301" is the HTTP status code for "Moved Permanently". When a browser or crawler requests the old URL, the server replies with the code and the new location, and the request follows automatically. A 308 is also permanent; 302 and 307 are temporary.
Google's guide to redirects and Google Search explains that permanent server-side redirects are a strong signal that the target should become canonical, while temporary redirects are a weak signal. It lists other methods (meta refresh, JavaScript redirects) and recommends server-side redirects where possible.
Good redirect practice:
- Redirect to the closest equivalent page, not to the home page. Redirecting many unrelated pages to the home page may be treated as a soft 404.
- Avoid chains and loops. A → B → C wastes crawling and slows visitors. Point A straight to C.
- Keep redirects in place for a long time. Google recommends keeping them for at least a year after a site move, and longer is safer because people and other sites keep using old links.
- Update internal links to point to the new URLs, rather than relying on redirects.
Redirects are also a fix for duplicate content and keyword cannibalisation, because they combine signals onto one URL.
Why it matters when hiring an agency
Redirects are where many site migrations go wrong. Ask any agency handling a redesign, platform change or domain move how it builds and tests the redirect map, and how it will monitor errors afterwards.
In audits, expect redirect chains, redirects to irrelevant pages and internal links pointing at redirected URLs to be flagged. Our Google Index Checker shows the status code and final URL for any page, which is a quick way to confirm a redirect behaves as intended.