HTTP 301 Moved Permanently

What it means

On a 301, browsers and search engines continue to the URL in the Location header. Browsers often cache permanent redirects, so a misconfigured 301 is hard to undo quickly for visitors. When redirecting a POST request, the browser may switch the method to GET; use 308 to preserve the method.

Most common causes

• Moving to a new domain or from HTTP to HTTPS.
• Changing the URL structure (e.g. dropping .html or /index.php).
• Consolidating the www and non-www versions.
• Merging two pages with the same content.

What you can do as a visitor

1. The redirect is usually correct. If it goes to the wrong page, clear your browser cache, because a 301 stays cached.
2. If the browser keeps going round in circles, it is a redirect loop. See ERR_TOO_MANY_REDIRECTS.

What the site owner or developer should do

1. Redirect straight to the final URL, without chains (A→B→C).
2. Redirect to a page with matching content, not everything to the homepage.
3. Update internal links, canonicals and the sitemap to the new URL.
4. Keep redirects in place for at least a year, and longer after a domain move.

Impact on SEO and Google

Google treats a 301 as a strong signal that the new URL is canonical and passes ranking signals to it. Chains and loops slow down crawling, and a redirect to an unrelated page may be treated as a soft 404.