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
302 is treated like 301 when the target gains authority
If you use a 302 redirect, once the target page has other authority signals, the redirect gets treated like a 301.
302s Are Indexed, 301s Aren’t
Google always use the content from the final destination page, but will display either the redirecting URL for a 302 redirect, or the the final destination for a 301 redirect. They ignore any content on the redirecting URL.
Redirecting to 404 is OK
A 302 redirect to a 404 page is OK
Google May Choose an HTTP URL as Canonical if the HTTPS has Mixed Content
Google will try and choose a canonical URL which does not have mixed content issues from http/https. I.e. if there is an https version of a page that DOES have mixed content issues, but an http version that does NOT have mixed content issues, then the http version could be used. If however, there are very strong signs to use that https version coming from the website, (such as redirects or rel=canonicals) then Google will still use the https version even though it has mixed content issues.
304 Headers Improve Crawl Efficiency
304 If Modified Since headers improve crawl efficiency.
Googlebot Can Be Redirected to Canonical URLs
John says that althought it’s technically cloaking, it’s actually OK to redirect Googlebot from URLs with tracking parameters to canonical URLs, but allow users not to be redirected, so they can be tracked in analytics.
It isn’t possible to say which ranking factors are most important because this changes dependent all the time, from day to day, query to query etc. As such it isn’t possible to say if a ranking factor, like Rank Brain, is going to become more influential in the future
302 redirects are initially ignored, and the original page will continue to rank, but after a period of time, they treat it as 301 instead and drop the original page in favour of the redirect target.
Redirect Expired Pages to Alternatives or 404
Out of stock/expired pages can be managed in a variety of ways. If there is a relevant alternative product, or a category page with good alternatives, a redirect is OK, otherwise a 410/404 is best.
Keep 301 redirects in place as long as possible
Although Google are able to recognise a site move as a permanent move which doesn’t require the redirect, although some links may not remain completely redirected.
If 302s are treated like 301s eventually, will they pass PageRank?
302 redirects will pass PageRank anyway, so yes.