301 redirect

What it means

A 301 redirect is a web server response telling both the browser and search engines that a page has moved permanently to a new address. The visitor lands in the right place automatically and the search engine gradually replaces the old address in its index with the new one. 301 is the HTTP status code meaning moved permanently.

For SEO it matters that a 301 redirect passes most of the signals the old page accumulated to the new address, above all the value of backlinks. Without a redirect the old address would return a 404 error, links would lead nowhere and rankings in search results would be lost.

A permanent redirect must be distinguished from a temporary one, such as code 302 or 307, which tells the search engine the original address will return. For a permanent change the correct code is 301 or its modern equivalent 308. A redirect is also not the same as a canonical URL, which merely marks the preferred version among several existing pages.

How it works in practice

Redirects are essential when changing domain, moving from HTTP to HTTPS, restructuring URLs, merging similar articles or removing a product from an online store. Before any such change, prepare a map of old and new addresses in which each old page points to the closest matching content, not everything to the homepage.

After launch we recommend checking that the redirects work, that they do not form chains of several redirects in a row, and that internal links and the sitemap already contain the new addresses. In webmaster tools, crawl errors and the number of indexed pages should be monitored for several weeks.

Redirects are set up at server level, in hosting configuration, in the content management system or, for static sites, in the hosting platform's configuration. They should remain active for a long time, ideally permanently, because old links on other sites, in emails or in printed materials live on for years.

What to watch out for

The most common mistake is redirecting all old addresses to the homepage. Search engines often treat this as a so-called soft 404 and do not pass on link value. Redirect chains and loops are equally harmful: they slow loading and can block indexing completely.

Take care when migrating a site to a new system. The new platform may use a different URL format, and without a redirect map the company loses search traffic built up over years. Redirects should be prepared before the new site launches and tested on a staging version.