301s

301s, or 301 redirects, refer to the HTTP status code 301 Moved Permanently. They indicate that the resource at a given URL has been permanently relocated to a new URL provided in the Location response header. Clients, including browsers and crawlers, should update their references and use the new URL in future requests.

When a 301 response is received, the client follows the Location header to retrieve the resource at the new URL. The redirect may be cached by browsers and intermediary caches, which can minimize subsequent requests to the old URL. The original URL should ideally no longer serve content or should return an appropriate status if decommissioned.

Common uses include site restructuring, URL reorganization, domain migrations, or canonicalization where multiple URLs point to the same content. They are also used to permanently move content from HTTP to HTTPS or to a different domain or path.

SEO considerations: most major search engines pass a substantial portion of ranking signals from the old URL to the new one through a 301 redirect, though exact behavior can vary. To preserve crawl equity, minimize redirect chains and ensure internal links and sitemaps point directly to the final URL.

Best practices: implement 301 redirects on the server side and test with multiple user agents, ensure the destination returns a successful response, avoid redirect loops, and monitor analytics to confirm users and crawlers reach the intended URL. If a redirect is necessary, avoid chaining through several intermediate URLs and aim for a single, direct redirect to the final URL.