Knowledge base v2.13.0 · Community edition · data through 2 October 2026
Topic · Indexing
Google treats a site migration as deduplication across sites: redirects are trusted strongly for clustering, and whether a redirect is permanent or temporary only decides which URL becomes canonical, so with a 302 Google keeps showing the source URL. The URLs that lose are kept as 'alternate names', which is why a site: query for an old domain still lists old URLs after a migration and why people searching for an old brand can still see the old domain; Google's redirects guide calls this normal and says it fades. Google's closing advice on duplication included using redirects for site migrations and keeping canonical signals clear, and a community speaker showed a canonical chain running through a 301 to another subdomain. For a product out of stock for months, a Google Q&A slide said keeping or redirecting the page depends on how important it is to users, who may wait or pre-order; Google's guide to pausing a business recommends staying online and updating Product structured data with current availability. Google also said a site should not move to country-code domains just because a ccTLD is a strong country signal. Day 3 put a site move in time: Google treats it as a complex canonicalization in which every signal of the old site is recalculated and moved, so a move takes one to three months on average, a few weeks for a small site and up to about a year in the worst case, because Google's slowest signal is recalculated about once a year (said at the event, in a partly uncertain passage of the recording; Google's site move guide says a few weeks for most pages of a small to medium site and to keep redirects for at least a year). The second recordings added two migration case studies and Google's own example. In the Day 1 Q&A Google described consolidating a dozen or so language blogs, a Help Center and its old developers site into one site: the first priority was to identify the popular URLs and protect them, and duplicated language versions were merged by giving both old URLs one target path to redirect to. Asked how to plan a migration that does not leave many URLs unindexed, a panelist said the answer is probably not sitemaps but deciding what matters to the business, such as whether to consolidate languages; listing the new URLs in a sitemap is probably a good idea and cannot hurt, but it is not the main tool. As a fun fact the panel said JavaScript was used for the language-consolidation redirects in Google's own migration, because it was the only option available to the person doing it (said at the event; the recording does not make fully clear how it was used). Author’s view: Google's redirects guide says Google Search follows JavaScript redirects only after rendering and recommends them only when server-side or meta refresh redirects are impossible, and its site move guide asks for server-side 301 or 308 redirects, so Google's own JavaScript was a fallback, not a pattern to copy. Author’s view: this matches Google's November 2020 move to Google Search Central, about six years before the event rather than the four or five said on stage. Cherry Prommawin said Google follows permanent and temporary redirects and indexes whatever the target returns (Google's docs: up to 10 hops by default), and Day 2's opening Q&A added that several sloppy migrations on one domain cause many short-term effects on indexing as well as crawling, and contrasted out-of-stock products buyers will wait for with easily replaced ones they simply swap. In Day 2's Lightning session E a community speaker merged two competing loan-comparison sites into one brand: every URL was given a keep, merge or remove decision, an old URL got a 301 only when a new page served the same intent, removed URLs were never redirected to the homepage, and new sitemaps, a Change of Address in Search Console and updated internal links followed, as Google's site move guide advises; the speaker reported traffic growth from the first day and revenue up 100% month over month (the speaker's figures). A second community speaker ran a post-acquisition migration around one redirect map giving every old URL an approved destination and an owner, froze the inventory (export, crawl, sitemap, search data, logs) before launch, and after it checked each URL's route, content and lead rather than its 200 status; he cited an unnamed study's median recovery time of 304 days but said broken routes need action at once. Author’s view: return 404 or 410 for removed content rather than redirecting it to an unrelated page, and report indexing and traffic recovery separately, since Google's guide measures the switch of indexed URLs in weeks while traffic can take far longer.
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Counts are claims that name the thing. All things
What to do
In a post-migration analysis of over 200,000 lines of search traffic data and more than 45,000 pages, where many URLs had been merged into one, an agency set the rules for what counted as the same page and used AI to match old and new addresses and roll the traffic up per page.
Speaker James PowleyIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
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.
Speaker Cherry PrommawinIn Day 1, 14:35 · How crawling errors affect SearchEvidence transcript
Used byrequirement DEV-CAN-01
An audience member asked how to plan a site migration so that it does not leave large numbers of URLs not indexed.
From the audienceIn Day 1, 16:35 · Q&AEvidence transcript
In a migration about four or five years before the event, Google consolidated 12 or 14 of its blogs in different languages, a Help Center and its old developers site into one site.
Speaker not identifiedIn Day 1, 16:35 · Q&AEvidence transcript
The first priority in Google's own site consolidation was to identify the popular URLs people care about and make sure the migration did not damage them.
Speaker not identifiedIn Day 1, 16:35 · Q&AEvidence transcript
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.
Speaker not identifiedIn Day 1, 16:35 · Q&AEvidence transcript
Used byrequirement DEV-CAN-10
Asked how to plan a migration that does not leave many URLs unindexed, a Google panelist said the answer is probably not sitemaps: decide what matters from the business's perspective (for example whether to consolidate languages); listing the new URLs in a sitemap is probably a good idea and cannot hurt, but it is not the main tool.
Speaker not identifiedIn Day 1, 16:35 · Q&AEvidence transcript
Used byrequirement DEV-CAN-09
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).
Speaker not identifiedIn Day 1, 16:35 · Q&AEvidence transcript
Used byrequirement DEV-CAN-01
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.
“Any content Google receives from the redirecting URL is ignored, and the final target URL's content is processed instead.”
Publisher GoogleAnnotates Day 1, 14:35 · How crawling errors affect Search
Used byrequirement DEV-CAN-01glossary term Redirect chain
The consolidation described on stage matches Google's November 2020 move from Google Webmasters to Google Search Central, which moved its main blog, 13 localized blogs and the Search help content of the Search Console Help Center to its developer site: about six years before the event, not the four or five said on stage.
Author Ibrahim AnjroAnnotates Day 1, 16:35 · Q&A
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.
Author Ibrahim AnjroAnnotates Day 1, 16:35 · Q&A
Used byrequirement DEV-CAN-01
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 audienceIn Day 2, 10:15 · Welcome to indexing day!Evidence slide photo, transcript
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.
“It depends on the importance of the PDPs to the users.”
Wording checked against the slide or recording
Speaker Gary Illyes, Cherry PrommawinIn Day 2, 10:15 · Welcome to indexing day!Evidence slide photo, transcript
Used byrequirement DEV-ERR-04
Google's Q&A slide on out-of-stock product pages said users might wait months for some products, or even pre-order them if the site offers pre-ordering.
Speaker Gary Illyes, Cherry PrommawinIn Day 2, 10:15 · Welcome to indexing day!Evidence slide photo, transcript
Used byrequirement DEV-ERR-04
Google keeps the other URLs of a duplicate cluster as 'alternate names': equivalent URLs with the same content that Google still tracks as alternate versions of the representative URL.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence slide photo, transcript
Used byglossary term Alternate names
Alternate names are why a site: query for an old domain still shows the old domain's URLs after a site migration, which site owners often misread as a migration that is not working.
“FYI "alternate names" is why you see old domains in site:-queries”
Wording checked against the slide or recording
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence slide photo, transcript
Used byrequirement DEV-CAN-09
After a rebrand that changes the domain (the slide's example was johns-bikes to slow-bikes), Google can still show the old domain to people who search for the old brand by name, in navigational and branded queries.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence slide photo, transcript
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.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence slide photo, transcript
Used byrequirements DEV-CAN-05, DEV-URL-05
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.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence slide photo, transcript
Used byrequirement DEV-CAN-02
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.
Speaker Tobias SchwarzIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence slide photo
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.
Speaker Tobias SchwarzIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence slide photo
An audience member asked how several sloppy migrations on the same domain can affect Googlebot's crawling.
From the audienceIn Day 2, 10:15 · Welcome to indexing day!Evidence transcript
Google answered that several sloppy migrations on one domain can cause many effects in the short term, and noted that migrations concern indexing as well as crawling, a subject a later Day 2 talk would cover.
Speaker not identifiedIn Day 2, 10:15 · Welcome to indexing day!Evidence transcript
Google contrasted out-of-stock products a buyer will wait for, such as a rare watch battery that matters to them, with easily replaced products, such as a particular cheese, for which the buyer simply picks a similar product instead of waiting.
Speaker not identifiedIn Day 2, 10:15 · Welcome to indexing day!Evidence transcript
Google treats a site migration as deduplication across sites, in which the site owner says the old and the new domain are the same and that Google should pick the new domain, so deduplication also helps Google handle migrations.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence transcript
Used byrequirement DEV-CAN-09
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.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence transcript
Used byrequirement DEV-CAN-09
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.
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence transcript
Used byrequirement DEV-CAN-01
Whether a redirect is permanent or temporary matters only for choosing the canonical, not for clustering the URLs together.
“the permanent redirect really only matters for canonicalization, not for clustering.”
Speaker John MuellerIn Day 2, 11:55 · Handling web duplicationEvidence transcript
Used byrequirement DEV-CAN-01
Canonical chains can run through canonical links alone, through a server-side redirect between members, or through a client-side redirect between members.
Speaker Tobias SchwarzIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Canonical loops can also run through server-side or client-side redirects, not only through canonical tags.
Speaker Tobias SchwarzIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
In a community case study, two of the first loan-comparison websites in Poland did exactly the same thing, so they competed with each other for the same users, the same keywords and the same space in search results.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker said running two competing sites in one market meant keeping up twice with changes in how people search and in what Google values, instead of putting all resources behind one site.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
In a community case study, an acquisition by a group of loan-comparison brands (operating in eleven markets) prompted the merger of two competing portals into one brand, which the speaker framed as creating order rather than only a technical migration.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker set three goals before any technical work on a two-site consolidation: lower costs (infrastructure, maintenance and content paid for only once), one strong brand focused on one specialization, and a simple structure instead of hundreds of similar URLs competing with each other.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Before choosing which of two domains to keep in a consolidation, a community speaker's team checked both domains for past penalties and compared their traffic, conversion and revenue.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
In a community case study, every URL of both domains was exported, compared on traffic, conversion, backlinks, revenue and rankings, and given one of three decisions: keep, merge or remove.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
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).
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-10
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.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-10
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.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-09glossary term Change of Address tool
During a domain consolidation, a community speaker's team merged the analytics of both sites so that no historical data was lost.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker listed the technical SEO goals of a two-site consolidation as lighter pages, faster loading and no crawl budget spent on content that no longer mattered.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
After a domain consolidation went live, a community speaker's team checked Search Console every day, ran full site crawls and compared the numbers with the pre-migration baseline for months.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-09
A community speaker reported that after consolidating two loan-comparison sites into one domain, traffic grew from the first day, with no drop or waiting period.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker reported that revenue grew 100% month over month after the consolidation (the speaker's figure, period not stated), although the site had been cut from over 2,000 URLs to about 100.
Speaker Martyna AğanoğluIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community talk on a still unfinished migration, after a client bought a company whose site had to fit into one product line, presented the decisions behind the migration rather than its results.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker argued that migrations are hard because of people rather than technology: two companies, two teams, a dozen stakeholders and a board that set a deadline before anyone opened the CMS.
“I think there are no complex migrations. There are complex people.”
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker named four kinds of post-acquisition site migration: absorb (one site integrates into the other), keep apart, merge (two or three sites into a new one), and plug in (a full site becomes a section of the other site).
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker said a migration should be run around one document, the redirect map, which gives every old URL an approved destination.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-10glossary term Redirect map
A community speaker's four tips before mapping a migration: agree what to keep and retire with an owner for every decision, review what to retire with data, prioritise by business value and not only traffic, and set expectations with an owner to escalate to.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker advised asking support and sales which pages make buyers buy, and preparing the destination with relevant content and internal links before a migration launches.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker said most migration failures look technical but trace back to a decision nobody made; in the migration presented, more than 7,000 URLs still had no approved destination at the time of the talk.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker recorded each migration decision per URL: old URL, new URL, what must survive (for example a product answer and a demo request), who approves, and the test that proves it works.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byglossary term Redirect map
A community speaker advised asking other teams during a migration about everything a crawler cannot reveal, such as sales workflows or legal requirements.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
For migrations with many URLs, a community speaker suggested letting a similarity score propose redirect destinations and having people review the critical pages.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
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.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-10
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.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
Used byrequirement DEV-CAN-10
A community speaker's three post-migration checks per URL: the route (the old URL reaches its destination), the answer (the approved content is still there) and the lead (a demo request still reaches the CRM); automate them, but have people check critical journeys.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker advised giving moved content its own baseline, because site-wide totals can hide lost pages and lost search queries.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker cited a recent study (not named) that reported a median recovery time of 304 days after a site migration.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
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.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker advised telling users of a migrated brand that they are in the right place, through emails, a press release and a blog post, to keep the trust built with the old brand.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker said reputation travels with a migrated product: a good product takes its reviews and links along, and a product nobody likes takes its complaints along.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A community speaker summed up migration planning in three questions: what survives, who approves, and what test shows the migration actually works.
Speaker David Carrasco PamiesIn Day 2, 12:05 · Lightning session E: Managing Duplicates and Site MovesEvidence transcript
A separate ccTLD for each country version is not necessarily better, even though the ccTLD is one of the strongest country signals, and sites should not move their domain for that reason.
“Don't try to move your domain now.”
Speaker GoogleIn Day 2, 14:15 · Focusing on Internationalisation and LocalisationEvidence transcript
Used byrequirement DEV-INT-09
The Day 2 poster topics included technical SEO testing in CI/CD pipelines, internal links that move rankings, Search Console's URL Inspection tool and API, getting everyone on board during complex site migrations, a CMS migration from WordPress to Contentful, the 'global Spanish' problem and going beyond prompts.
Speaker Community speakersIn Day 2, 14:45 · Poster session H: IndexingEvidence transcript
Google's guide to temporarily pausing an online business recommends that a shop expecting to sell again within weeks or months stays online with limited functionality, such as a disabled cart, and updates its Product structured data to show current availability.
Publisher Google Search CentralAnnotates Day 2, 10:15 · Welcome to indexing day!
Used byrequirements DEV-ERR-04, DEV-SDA-08, DEV-SRV-03
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.
Publisher Google Search CentralAnnotates Day 2, 10:15 · Welcome to indexing day!
Used byrequirements DEV-CAN-01, DEV-ERR-04
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.
“This is normal and as users get used to the new domain name, the alternate names will fade away without you doing anything.”
Publisher Google Search CentralAnnotates Day 2, 11:55 · Handling web duplication
Used byrequirements DEV-CAN-01, DEV-CAN-09glossary term Alternate names
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.
Publisher Search Central blog (12 February 2009)Annotates Day 2, 12:05 · 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.
Publisher Google Search CentralAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
Used byrequirement DEV-CAN-10
Google's site move guide says to submit a Change of Address in Search Console when moving from one domain or subdomain to another, to submit the new sitemap, and to change internal links on the new site from the old URLs to the new ones.
Publisher Google Search CentralAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
Used byrequirement DEV-CAN-09glossary term Change of Address tool
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.
Author Ibrahim AnjroAnnotates Day 2, 10:15 · Welcome to indexing day!
Used byrequirement DEV-ERR-04
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.
Author Ibrahim AnjroAnnotates Day 2, 11:55 · Handling web duplication
Used byrequirement DEV-CAN-09
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.
Author Ibrahim AnjroAnnotates Day 2, 11:55 · Handling web duplication
Used byrequirement DEV-CAN-01
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.
Author Ibrahim AnjroAnnotates Day 2, 11:55 · Handling web duplication
Used byrequirement DEV-CAN-05
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.
Author Ibrahim AnjroAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
Used byrequirement DEV-CAN-04
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.
Author Ibrahim AnjroAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
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.
Author Ibrahim AnjroAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
The 304-day median recovery a community speaker cited from an unnamed study and Google's site move guide (a few weeks or more for a medium-sized site until Google shows the new URLs, longer for larger sites) measure different things: indexing can switch within weeks while traffic recovery can take far longer, so plan and report on both.
Author Ibrahim AnjroAnnotates Day 2, 12:05 · Lightning session E: Managing Duplicates and Site Moves
Google treats a site move as a complex canonicalization process in which every signal of the old site is recalculated and moved to the new one, and every indexing process has to run.
Speaker Gary IllyesIn Day 3, 15:45 · How long does it take to..?Evidence transcript
A site move can finish within a few weeks for a small site, takes one to three months on average, and in the worst case about a year.
Speaker Gary IllyesIn Day 3, 15:45 · How long does it take to..?Evidence transcript
Used byrequirements DEV-CAN-09, DEV-MON-10
Gary Illyes said a site move can take up to about a year in the worst case, because Google's slowest signal is recalculated only about once a year (some words of this passage are uncertain readings).
Speaker Gary IllyesIn Day 3, 15:45 · How long does it take to..?Evidence transcript
Used byrequirement DEV-CAN-09
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.
Publisher Google Search CentralAnnotates Day 3, 15:45 · How long does it take to..?
Used byrequirement DEV-CAN-09
Google's site move guide says that, as a general rule, a small to medium-sized site can take a few weeks for most pages to move and larger sites take longer, depending on the number of URLs and server speed.
Publisher Google Search CentralAnnotates Day 3, 15:45 · How long does it take to..?
Used byrequirement DEV-CAN-09
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.
Author Ibrahim AnjroAnnotates Day 3, 15:45 · How long does it take to..?
Used byrequirement DEV-CAN-09
The consolidation described on stage matches Google's November 2020 move from Google Webmasters to Google Search Central, which moved its main blog, 13 localized blogs and the Search help content of the Search Console Help Center to its developer site: about six years before the event, not the four or five said on stage.
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).
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.
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).
Google contrasted out-of-stock products a buyer will wait for, such as a rare watch battery that matters to them, with easily replaced products, such as a particular cheese, for which the buyer simply picks a similar product instead of waiting.
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.
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).
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.
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.
Asked how to plan a migration that does not leave many URLs unindexed, a Google panelist said the answer is probably not sitemaps: decide what matters from the business's perspective (for example whether to consolidate languages); listing the new URLs in a sitemap is probably a good idea and cannot hurt, but it is not the main tool.
A community speaker listed the technical SEO goals of a two-site consolidation as lighter pages, faster loading and no crawl budget spent on content that no longer mattered.
Four ways to manage crawl budget: use HTTP cache control, have good site navigation, restrict crawlers' access to faceted navigation and action URLs, and improve or remove useless content.
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.
A soft 404 is a page that should return an error status code but returns HTTP 200; from a crawling point of view it looks indexable, but because it has no real content Google throws it out of the index.
Google treats a site move as a complex canonicalization process in which every signal of the old site is recalculated and moved to the new one, and every indexing process has to run.
Google treats a site migration as deduplication across sites, in which the site owner says the old and the new domain are the same and that Google should pick the new domain, so deduplication also helps Google handle migrations.
Rests on 14 claims, 14 of them in this topic
Use permanent server-side redirects (301 or 308) for moved URLs, straight to the final URL
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Redirect an old URL only to a page with the same intent, and return 404 or 410 when there is none
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Keep temporarily out-of-stock product pages live with 200 and their current availability
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Make all canonical signals agree: redirects, rel=canonical, internal links, sitemaps and hreflang
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Serve one host over HTTPS with a valid certificate and redirect every other origin to it
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Point every canonical directly at a final URL that returns 200, is indexable and is linked
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Choose ccTLDs, subdomains or subdirectories by business needs, and never URL parameters
Rests on 6 claims, 1 of them in this topic
Plan releases and fixes around Google's processing times, and judge results only after them
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Mark up merchant listings completely, with validity dates for sale prices
Rests on 7 claims, 1 of them in this topic
Answer planned maintenance and short outages with 503, for a day or two at most
Rests on 11 claims, 1 of them in this topic
Publish XML sitemaps listing only canonical, indexable URLs with accurate lastmod
Rests on 11 claims, 1 of them in this topic