Redirects
URL redirection is a process put in place to forward site visitors to an alternative page when the page they are looking to view is no longer live on the site. Redirects may be implemented for migration purposes, as well as for site re-architecture and when pages naturally expire. They can also be used to consolidate ranking signals. Our SEO Office Hours notes below cover the different redirection types and explore how Google understands these.
Further reading: The ABCs of HTTP Status Codes
Canonicalising to Redirects Can Increase Time Taken to Index Preferred Version
Canonicalising to redirects can increase the time taken for Google to decide which version to index, especially if these pages aren’t identical. Google also looks at other signals such as internal linking and sitemap files to make this decision.
Let Google Know About Site Merging Through Redirects
Redirects are the best way to help Google process a site merging. Bear in mind that site merging or site splitting takes more time for Google to process than a site migration.
301 Redirection Doesn’t Ensure the Final Destination URL Will be Indexed
Having a 301 redirect doesn’t mean that the final destination URL will be the page that is indexed. You need to make sure that you have correct canonicalization, internal linking and hreflang markup pointing to the correct page.
Search Console Change of Address Takes a Couple of Days
A change of address submitted to Search Console takes a couple of days to take effect when a redirect is in place.
Expired Content Can be Redirected, 404’d or Noindexed
There is no one correct way to deal with expired content on a site. If there is a relevant page that replaces the expired one then you can implement a 301 redirect. If there is no replacement page, then you can leave the page as 200 saying that it is no longer valid and use either a 404 or noindex after a period of time.
Use 301s to Migrate a Subdomain to a Subfolder
You can’t use the Search Console site migration tool to move a subdomain to a subfolder, but 301 redirections are fine.
Google Recommends Keeping Redirects For At Least One Year
Google recommends keeping redirects for one year minimum. This is because URLs will, in the worst case scenario, be crawled by Googlebot every six months, so a having the redirect in place for a year would give Google the chance to see that redirect at least twice.
Redirect Obsolete Pages to Replacement Pages
You can use a 301 redirect on e-commerce sites when one product page replaces an obsolete one.
Google Follows 5 Steps in a Redirect Chain at a Time
Googlebot will follow up to five redirects at a time, and crawl further redirect steps at a later date to find where redirect ends up, but Google recommends redirecting directly from the original URL to the final URL.
Keep Old Domains Redirecting Following a Domain Migration
John recommends retaining old domains following a domain migration and keep the redirects active for as long as possible.