Google's crawlers follow up to 10 redirect hops by default (some products' crawlers have other limits); content served by the redirecting URL is ignored and the final target's content is processed instead.
Thing · Concept
Redirects
Answers that send crawlers and users from one URL to another, server-side (permanent 301 and 308, temporary 302 and 307) or with JavaScript; a strong canonical signal and the core of a site move.
- Claims
- 61
- In Google’s docs
- 10
- Said at the event
- 37
- Not in docs
- 7
- Kit items
- 18
Google’s documentation 10
Documented in
Google's redirect documentation says that with a temporary redirect, such as a 302, Google Search shows the source page in search results and does not use the redirect as a signal that the target should be canonical.
Google Search Central · Day 2 · Welcome to indexing day!
Google's JavaScript guides say that when client-side routing makes a real 404 status impractical, a single-page app can avoid soft 404s by redirecting with JavaScript to a URL whose server returns 404, or by adding a robots noindex meta tag with JavaScript.
Google Search Central · Day 2 · Lightning session D: Rendering and JavaScript
For client-side rendered single-page apps, where meaningful status codes can be impossible or impractical, Google's documentation gives two ways to avoid soft 404s: a JavaScript redirect to a URL that returns a 404 status, or a noindex robots meta tag added with JavaScript.
Google Search Central · Day 2 · What is Google friendly JavaScript
Google's redirects guide says Google keeps track of both the source and the target of a redirect: one becomes the canonical, depending on signals such as whether the redirect is permanent or temporary, and the other becomes an alternate name that may appear in results when a query suggests the user trusts the old URL more. After a move to a new domain, old URLs may still show occasionally; the guide calls this normal.
Google Search Central · Day 2 · Handling web duplication
Google's canonical guide ranks the ways to signal a preferred canonical by strength: redirects and rel=canonical annotations are strong signals, sitemap inclusion is a weak signal, and combining methods makes them more effective.
Google Search Central · Day 2 · Handling web duplication
Google's 2009 Search Central blog post introducing rel=canonical says a canonical URL may be a URL that redirects: Google then processes the redirect as usual.
Search Central blog (12 February 2009) · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Google's site move guide says not to redirect many old URLs to one irrelevant destination such as the new site's home page, which can confuse users and might be treated as a soft 404, and to return a 404 or 410 for deleted or merged content that is not moved to the new site.
Google Search Central · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Google's documentation says Googlebot mostly crawls from US IP addresses and sends no Accept-Language header, so pages that change content or redirect by the visitor's perceived country or language may not have every version crawled, indexed or ranked; it recommends separate URLs annotated with hreflang.
Google Search Central · Day 2 · Focusing on Internationalisation and Localisation
Google's site move guide says to keep redirects for as long as possible, generally at least one year, so that Google can transfer all signals to the new URLs.
Google Search Central · Day 3 · How long does it take to..?
Said at the event 37
Slide and stage claims that name it, the ones Google’s documentation does not cover first.
Label
Grade
Day
Not in docs 7
Dave Smart said robots.txt is checked for every URL in a redirect chain and crawling stops at the first blocked one; in his example a site redirected through /cart/ with JavaScript to set the local currency and back, and because /cart/ was disallowed the page was reported as blocked.
Dave Smart · Day 1 · Lightning session B: Robots.txt
Dave Smart said this applies to all redirects, not only JavaScript ones; his examples: a redirect through an external authorisation service that is blocked by its own robots.txt, content that moved through several URLs over the years with one of them later blocked, and unexpected redirects, such as one served only to Googlebot's user agent.
Dave Smart · Day 1 · Lightning session B: Robots.txt
A Google panelist said, as a fun fact, that JavaScript was used for the language-consolidation redirects in Google's own site migration, because it was the only option available to the person doing it (the recording does not make fully clear whether the JavaScript performed the redirects or built the mapping).
Not in docsD2-C010
Google answered on a Q&A slide that whether to keep a temporarily out-of-stock product page or redirect it depends on how important that product page is to users.
Canonical chains can run through canonical links alone, through a server-side redirect between members, or through a client-side redirect between members.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Canonical loops can also run through server-side or client-side redirects, not only through canonical tags.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
A community speaker said that at best a search engine's heuristic would treat a canonical loop through redirects as self-referencing canonicals, and doubted that this is often done when the loop runs through a client-side redirect.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Consistent with docs 18
HTTP status codes fall into five classes, 1xx informational, 2xx success, 3xx redirection, 4xx client error and 5xx server error, and each class affects crawling differently.
Cherry Prommawin · Day 1 · How crawling errors affect Search
When Search Console says a URL is blocked by robots.txt but the file does not block it, check whether the URL redirects and test every URL in the chain.
Dave Smart · Day 1 · Lightning session B: Robots.txt
A community speaker said similar URLs are an indicator of duplicate content, broken links, unnecessary redirects and other technical issues.
Tobias Schwarz · Day 1 · Lightning session C: Crawling
A community speaker advised that a web application compute the expected URL for every request, for example with reverse routing from the page type and ID, and redirect or return an error page when the requested URL differs.
Tobias Schwarz · Day 1 · Lightning session C: Crawling
For query parameters, a community speaker advised checking that every parameter in a request is actually used and in the expected order, and otherwise redirecting to the expected URL with only the used parameters in the correct order.
Tobias Schwarz · Day 1 · Lightning session C: Crawling
One fix for parameter variants of a URL is to work out the normalised URL and redirect the variants to it: the redirects cost crawl budget at first, but leave the site with a clean slate.
Where content was duplicated across languages, Google's own site consolidation redirected two language versions into one, giving both old URLs one target path to redirect to.
Google builds duplicate clusters from four kinds of input: redirects, content, rel=canonical, and a 'magic bucket' of other things.
Google trusts redirects very much for clustering, because a redirect is a clear sign that there is one version of the content; Google keeps track of both URLs but stores only one copy of the content.
Whether a redirect is permanent or temporary matters only for choosing the canonical, not for clustering the URLs together.
Consistent with docsD2-C387
Google named three considerations when picking a representative URL: hijacking across pages or sites, user experience (the page can load, meta refresh, security) and site-owner signals (redirects, rel=canonical, sitemaps).
Consistent with docsD2-C390
Clear site-owner signals about which URL should be canonical make a big difference to Google's choice; the speaker named redirects, listing only the preferred URL in sitemaps, and rel=canonical, which the speaker said also helps a bit.
Consistent with docsD2-C396
Google's closing suggestions on duplication: use redirects for site migrations, use HTTP result codes, don't block agents, check your rel=canonical links, use hreflang links to help Google localize, report weird canonicals in the forums, make secure pages that work, and keep canonical signals clear.
In a community case study, an old URL got a 301 redirect only when a new page served the same intent; URLs with no same-intent match were removed with an error status instead of being redirected (the exact code is unclear in the recording).
Martyna Ağanoğlu · Day 2 · Lightning session E: Managing Duplicates and Site Moves
A community speaker's team never redirected removed URLs to the homepage, even those that still brought traffic, because the aim was a clear signal about what the site is rather than keeping every visitor.
Martyna Ağanoğlu · Day 2 · Lightning session E: Managing Duplicates and Site Moves
A community speaker said a migration should be run around one document, the redirect map, which gives every old URL an approved destination.
David Carrasco Pamies · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Before a migration launches, a community speaker advised freezing the inventory (CMS export, crawl, sitemap, search data and logs), saving all content and approving the redirect map.
David Carrasco Pamies · Day 2 · Lightning session E: Managing Duplicates and Site Moves
A community speaker warned that HTTP 200 responses across a new domain show only that the URLs work, not that the content users came for is still there, so after launch the redirect map becomes the test.
David Carrasco Pamies · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Confirmed by docs 4
Google follows 3xx redirects, permanent (301, 308) and temporary (302, 307), to the new location, and whether content gets indexed depends on what the redirect target returns.
Cherry Prommawin · Day 1 · How crawling errors affect Search
In an app routed with the History API, when a user reaches a page that does not exist, Erin Sparling suggested asking how they got there and redirecting to a real 404 page.
Erin Sparling · Day 2 · What is Google friendly JavaScript
When someone searches for an old domain after a migration, Google shows the old URL as an alternate version because that is what was searched for, and relies on the redirect to take the user to the new site.
The technical steps of a community speaker's domain consolidation included submitting new sitemaps, filing a change of address in Search Console and updating internal links so the new pages did not rely on redirects alone.
Martyna Ağanoğlu · Day 2 · Lightning session E: Managing Duplicates and Site Moves
Nothing to verify 8
StageD1-C490
An audience member asked what happens to thousands of crawled and indexed paginated category and tag pages if they are replaced by a single page with a JavaScript load-more button, and whether the old pages should then redirect to the canonical first page.
From the audience · Day 1 · Q&A
An audience member asked whether a product detail page that is out of stock for two to three months should keep returning 200 with links to similar products, or be 302-redirected to a similar product or to its parent product listing page.
From the audience · Day 2 · Welcome to indexing day!
StageD2-C409
A community speaker said it helps to view small canonical groups as a graph that shows any redirects between members, together with the indexability of each member page.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
In the real-world canonical group shown on screen (a German-language travel magazine section, site not named), a feed URL's canonical pointed to a URL on another subdomain that 301-redirected to the leader, a canonical chain through a server-side redirect.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
The crawler report shown on screen rated a canonical group member that issues a redirect instead of displaying content as an error, and flagged canonical links whose target returns a non-200 status or is itself a redirect.
Tobias Schwarz · Day 2 · Lightning session E: Managing Duplicates and Site Moves
StageD2-C901
For migrations with many URLs, a community speaker suggested letting a similarity score propose redirect destinations and having people review the critical pages.
David Carrasco Pamies · Day 2 · Lightning session E: Managing Duplicates and Site Moves
StageD2-C907
A community speaker said a long expected recovery after a migration is no reason to wait: broken redirect routes and blocked pages need action immediately.
David Carrasco Pamies · Day 2 · Lightning session E: Managing Duplicates and Site Moves
StageD3-C489
Nik Vujic said some keyword cannibalization is fine because it is logical, but for bad cannibalization his agency groups all of an article's Search Console queries and then decides whether to redirect the pages or rewrite and split the content.
Nik Vujic · Day 3 · Lightning session L: Understanding SERPs and your users
Press and analysis 14
AnalysisD1-C421
Of the two answers a community speaker offered for a request to a URL variant (redirect, or an error page), Google's canonicalization guide favours the redirect: a redirect is a strong signal that its target should become canonical, while an error page throws away any links pointing at the variant.
Ibrahim Anjro · Day 1 · Lightning session C: Crawling
AnalysisD1-C542
Google's redirects guide says Google Search follows JavaScript location redirects only after rendering, may never see one if rendering fails, and should be used only when server-side or meta refresh redirects are impossible; its site move guide asks for server-side permanent redirects (301 or 308) where technically possible. The JavaScript in Google's own migration was a fallback ('my only option'), not a pattern to copy.
Ibrahim Anjro · Day 1 · Q&A
AnalysisD2-C014
Keep a product page that is out of stock for a few months live with a 200 status, show its availability on the page and in Product structured data, and offer pre-ordering where possible when users would wait for the product. Redirect it only when users would rather switch to a similar product than wait.
Ibrahim Anjro · Day 2 · Welcome to indexing day!
AnalysisD2-C193
In a single-page app, let the server return 404 for unknown routes where possible; otherwise use one of the two client-side fixes Google documents for error views: a JavaScript redirect to a URL that returns 404, or a robots noindex added with JavaScript.
Ibrahim Anjro · Day 2 · Lightning session D: Rendering and JavaScript
AnalysisD2-C358
After a migration, judge success by the new domain's indexing and traffic in Search Console rather than by a site: query on the old domain, and keep the old domain's redirects in place long term so searches for the old brand still reach the new site.
Ibrahim Anjro · Day 2 · Handling web duplication
AnalysisD2-C363
Use permanent redirects (301 or 308) for moves you want reflected in Search: a temporary redirect still groups the URLs, but it changes which URL Google is likely to pick as the canonical.
Ibrahim Anjro · Day 2 · Handling web duplication
AnalysisD2-C392
Google's duplication talk described rel=canonical as something that 'also helps a bit', while Google's canonical guide calls it a strong signal alongside redirects and calls sitemap inclusion weak; treat redirects and rel=canonical as the main levers and sitemaps as support.
Ibrahim Anjro · Day 2 · Handling web duplication
AnalysisD2-C400
Before a migration or template change, align every canonical signal for the preferred URL (redirects, rel=canonical, internal links, sitemap entries, hreflang and working HTTPS); Google says it follows the site owner only when the signals agree.
Ibrahim Anjro · Day 2 · Handling web duplication
AnalysisD2-C416
To audit canonicals at scale, resolve every crawled URL to the final URL its canonical links and redirects lead to, group URLs by that leader, and flag groups with more than one hop, a loop, several canonicals on one page, or a leader that is noindexed, blocked, non-200 or redirecting.
Ibrahim Anjro · Day 2 · Lightning session E: Managing Duplicates and Site Moves
AnalysisD2-C423
After a migration or a subdomain change, update rel=canonical tags to the new final URLs: canonicals still pointing at old, redirecting URLs create chains through server-side redirects like the one in the real-world example shown.
Ibrahim Anjro · Day 2 · Lightning session E: Managing Duplicates and Site Moves
AnalysisD2-C431
A leader reachable only through a canonical and a leader with weak link equity share one fix: point internal links, sitemap entries and redirects at the URL chosen as canonical, so the leader is both reachable for users and the strongest page in its group.
Ibrahim Anjro · Day 2 · Lightning session E: Managing Duplicates and Site Moves
AnalysisD2-C439
The crawler report shown at the talk rated a redirecting canonical target as an error, while Google's 2009 guidance accepts a canonical URL that redirects and says Google can follow canonical chains; the gap is one of severity, since both recommend pointing every canonical link straight at the final URL.
Ibrahim Anjro · Day 2 · Lightning session E: Managing Duplicates and Site Moves
AnalysisD2-C913
For URLs removed in a consolidation, return 404 or 410: Google's site move guide names those two codes, and Google's crawlers treat every 4xx code except 429 the same way, as content that does not exist, so the choice between them matters less than not redirecting to an unrelated page.
Ibrahim Anjro · Day 2 · Lightning session E: Managing Duplicates and Site Moves
AnalysisD3-C645
Keep migration redirects in place for at least a year and judge a site move after one to three months, not days: Google's speaker said its slowest signal needs about a year to be recalculated (a partly uncertain passage of the recording), and Google's site move guide says to keep redirects generally at least one year.
Ibrahim Anjro · Day 3 · How long does it take to..?
Built on these claims 18
Kit items about Redirects: their own words name it, or several of the claims they rest on do.
Developer requirements 13
Use permanent server-side redirects (301 or 308) for moved URLs, straight to the final URL
Rests on 10 claims, 10 of them naming Redirects; its own words name Redirects
Redirect an old URL only to a page with the same intent, and return 404 or 410 when there is none
Rests on 7 claims, 7 of them naming Redirects; its own words name Redirects
Rests on 14 claims, 6 of them naming Redirects; its own words name Redirects
Make all canonical signals agree: redirects, rel=canonical, internal links, sitemaps and hreflang
Rests on 6 claims, 4 of them naming Redirects; its own words name Redirects
Compute the expected URL for every request and redirect variants to it
Rests on 8 claims, 4 of them naming Redirects; its own words name Redirects
8 more
Never route a crawlable URL's redirects through a URL that robots.txt blocks
Rests on 4 claims, 3 of them naming Redirects; its own words name Redirects
Keep temporarily out-of-stock product pages live with 200 and their current availability
Rests on 5 claims, 3 of them naming Redirects; its own words name Redirects
Serve one host over HTTPS with a valid certificate and redirect every other origin to it
Rests on 4 claims, 2 of them naming Redirects; its own words name Redirects
Point every canonical directly at a final URL that returns 200, is indexable and is linked
Rests on 8 claims, 2 of them naming Redirects; its own words name Redirects
Return a real 404 for unknown routes in single-page apps, or use a documented client-side fallback
Rests on 7 claims, 2 of them naming Redirects; its own words name Redirects
Publish XML sitemaps listing only canonical, indexable URLs with accurate lastmod
Rests on 11 claims, 2 of them naming Redirects; its own words name Redirects
Never leave staging, preview or mirror copies of the site publicly crawlable
Rests on 2 claims, 1 of them naming Redirects
Do not redirect visitors automatically by IP address or browser language
Rests on 2 claims, 1 of them naming Redirects; its own words name Redirects
Also inglossary terms Redirect chain, Alternate names, Change of Address tool, HTTP status code classes, Redirect map
Connected things 25
Relations
- Used by Site move
1 claim, 1 documented
Google's site move guide says to keep redirects for as long as possible, generally at least one year, so that Google can transfer all signals to the new URLs.
- Affects Canonicalization
2 claims, 2 documented
Whether a redirect is permanent or temporary matters only for choosing the canonical, not for clustering the URLs together.
Google's canonical guide ranks the ways to signal a preferred canonical by strength: redirects and rel=canonical annotations are strong signals, sitemap inclusion is a weak signal, and combining methods makes them more effective.
Most often named with it
Things named in the same claim, with the number of claims they share.
- Canonicalization 18
- rel=canonical 14
- JavaScript 8
- Sitemaps 8
- 404 6
- Site move 5
- Search Console 4
- 200 3
- hreflang 3
- noindex 3
- robots.txt 3
- Single-page app 3
- Soft 404 3
- 410 2
- 4xx 2
- Duplicate content 2
Topics that feature it
- Redirects, site moves and alternate names 37
- Canonical graphs: chains, loops and leaders 11
- Canonical selection 11
- Duplicate content 9
- Soft 404s 7
- JavaScript SEO pitfalls and fixes 6
- Crawl errors 5
- Similar URLs and URL normalisation 4
- Sitemaps 4
- robots.txt rules 3
- Faceted navigation 2
- Measuring success in the AI era 2
- Pruning and consolidating content 2
- Country targeting 1
- Crawlable links 1
- Indexing statuses in Search Console 1
- Page language and language versions 1
- Pagination and "load more" 1
- URL discovery 1
- What's new in Search Console 1
- Working with Search Console data 1