301 redirect

What is a 301 redirect?

A 301 redirect is an HTTP response with status 301 Moved Permanently that sends browsers and search engines from an old URL to a new one. It tells Google the move is permanent, which Google treats as a strong signal that the new URL should be indexed in place of the old one and receive its ranking signals.

A 308 Permanent Redirect means the same thing but requires the browser to keep the request method, so a POST stays a POST. Google treats 301 and 308 the same. Google can also treat an instant meta refresh or a JavaScript redirect as permanent, but a server-side 301 is the most reliable.

Since 2016 Google has said that 3xx redirects do not lose PageRank, so you no longer need to worry about a fixed "loss" per redirect. What still costs you is pointing redirects at irrelevant pages or chaining them.

Why 301 redirect matters for SEO

301s are how you keep rankings and backlinks when URLs change: site migrations, moving to HTTPS, changing domains, merging pages and tidying URL slugs. Without them, old URLs return 404, their backlinks point nowhere, and visitors hit dead ends.

They also fix duplication. Redirecting http to https and non-www to www (or the other way round) makes sure only one version of each page can be indexed.

The target matters. Redirecting many removed pages to the homepage is often treated by Google as a soft 404, so the old pages’ value is not passed on. Redirect each URL to the closest relevant replacement.

How to set up a 301 redirect

1. Map every old URL to its new equivalent before you change anything. One-to-one mappings beat blanket redirects.
2. Set the redirect on the server, CDN or framework, not with JavaScript, so every crawler sees it.
3. Redirect straight to the final URL. Avoid redirect chains and update old redirects when you add new ones.
4. Update internal links, canonical tags and your XML sitemap to point at the new URLs, so you are not relying on the redirect.
5. Keep redirects in place for at least a year, and ideally indefinitely for URLs with backlinks.
6. Test with `curl -I` or a crawler that each old URL returns 301 and lands on a 200 page.

301 redirect example

# Nginx
location = /old-page {
  return 301 https://www.example.com/new-page;
}

# Apache (.htaccess)
Redirect 301 /old-page https://www.example.com/new-page

# What the server returns
HTTP/1.1 301 Moved Permanently
Location: https://www.example.com/new-page