Website Migration SEO Checklist: Domain Changes, Mergers and Platform Moves

Marketing · By ·

An orange detour sign with an arrow on a striped road barrier beside a rural road.

What goes on a website migration SEO checklist depends on what is moving. Google treats each kind of move differently, whether it is a new domain after a rebrand or merger, several sites folded into one, a new CMS, or a new host or CDN. In every case, decide the final address before anything moves, redirect every old URL to its new equivalent, tell Google and Bing in the tools that apply, and make sure search and AI crawlers can still reach the new site. Then watch the data for months.

If you are redesigning on the same domain and only the URLs change, start with our guide to redesigning a website without losing search traffic. It covers the URL inventory and redirect map in detail. This post covers the moves it leaves out.

Name the kind of move

Google’s documentation splits migrations into moves where URLs change and moves where they don’t. Search Console’s Change of Address tool applies to only the first two rows of this table.

What is changingTypical triggerChange of Address tool?
Domain (example.com to example.org)Rebrand, merger or spin-offYes, after redirects are live
Several sites into oneMerger, brand consolidationYes, one site at a time
Paths on the same domainRedesign, new CMS URL patternsNo (redirects and updated sitemaps)
HTTP to HTTPS, or www to non-wwwSecurity work, cleanupNo
Hosting or CDN, same URLsNew platform, new vendorNo

A merged firm wants a new name and a new platform launched on the same day. Google advises against it. Its own example is a site that wants a new domain, a new CMS and a new layout. It says to plan changes “one after the other, not everything at the same time.” Where you can, move the domain first with the old structure intact, then redesign. Google’s Change of Address help page warns that combining a move with a new content and URL structure means “you will probably see some traffic loss as Google might need to relearn and reassess the individual pages.”

Decisions to make before anything moves

These five belong in the first leadership meeting. If I could get only one settled there, it would be the final domain.

Settle the final domain

Change of Address can’t be chained straight away. Google says that “If you submit a change of address to redirect traffic from site A to site B, you can’t immediately submit another change of address from site B to site C.” If the merged firm’s name might change again after the partners vote, wait for the vote.

Budget for the old domain

Keep paying for the old domain. Google recommends “continuing to pay for the old domain for at least a year to prevent others from buying and using your abandoned domain for malicious purposes.” We’d keep it longer, since old letterhead and donor receipts still point to it.

Check a purchased domain’s history

If the new name comes with a domain you bought from someone else, Google tells you to make sure it is “clean of any outstanding issues from the previous owner.” Once you’ve verified it in Search Console, check for manual actions and for any URL removals the previous owner left behind, “especially a site-wide URL removal.”

Pick the window

If your traffic is seasonal, Google suggests moving “during the recurring traffic dips.” For a nonprofit whose giving peaks at year end, that can rule out November and December. For a firm, it means avoiding the weeks when you expect the most inquiries.

Plan for extra crawling

Tell your host before launch. After a URL-changing move, Google says it “will temporarily crawl your new site more heavily than usual,” because crawls of the old site are redirected on top of normal crawling. Don’t throttle Googlebot with error codes as a shortcut. Google’s crawl-rate page warns that a URL returning 500, 503 or 429 errors for multiple days “may be dropped from Google’s index.”

Moving to a new domain

Redirects go live first, then you tell Google. Your developer or agency runs these steps; you approve the domain and the timing, and sign off the redirect map.

  1. Verify every variant, old and new. Google’s site-move guide asks you to verify all variants of both sites in Search Console, such as www and non-www and both HTTP and HTTPS. You must own both the old and new properties, and you must use the same Google account to manage both.
  2. Put the redirects live. At minimum a 301 from the old homepage to the new one. Google recommends 301s for the canonical pages too, so every page that earns traffic or links needs its own one-to-one mapping.
  3. Submit Change of Address for each variant. The tool works at the domain level and “does not move any subdomains below the specified domain (including www).” Google asks you to submit it for every subdomain variant of the old domain, “even if you’re not actively using these variants currently.”
  4. Redo the Search Console housekeeping. If you uploaded a disavow file for the old site, Google recommends uploading it again for the new one.
  5. Update links you control. Point internal links on the new site at the new URLs and give each new URL a self-referencing canonical, as Google’s guide asks. Google also suggests asking the sites behind your highest-volume inbound links to update them, because redirects are slow for users.

For 180 days the tool tells Google to favour crawling and indexing the new site and forwards signals from the old one. It doesn’t remove anything. Old URLs can keep appearing in results if they are reachable and have no equivalent on the new site. After 180 days, Google “treats the old site as an unrelated site, if still present and crawlable.” If the move has to be reversed, you can cancel it within those 180 days.

On how long to keep redirects, Google gives two numbers on two pages. The Change of Address help says at least 180 days, longer if Google Search still sends traffic to them. The site-move guide says “generally at least 1 year” and suggests considering keeping them indefinitely for users. Plan for the longer one.

Bing’s old Site Move documentation is gone from bing.com, and we couldn’t confirm the tool is still offered. Verify the new domain in Bing Webmaster Tools and rely on the 301s. Bing also supports IndexNow, which lets you notify participating search engines of changed URLs, up to 10,000 per submission. Google is not among the participating endpoints the protocol lists.

Merging several sites into one

A merger can mean two or three established sites, each with its own links and rankings, going to one new address. Google’s Change of Address help page is direct. “Try not to combine multiple moves to a single location.” Moving A, B and C to D at once “can cause some confusion and traffic loss.” It suggests moving sites one at a time and waiting until traffic stabilizes before moving the next.

A sequence that follows that advice:

  • Move the strongest site first, typically the one whose domain or content the merged organization is keeping. Its redirects can then be one to one.
  • Map overlapping pages to the consolidated page. Redirecting several old URLs to one new page is fine with Google when the content was genuinely consolidated there, as when two firms’ estate planning pages become one. Sending everything to the new homepage “might be treated as a soft 404 error.”
  • Let retired content return a 404 or 410. Google’s site-move guide asks for one or the other when content isn’t moving. Google’s crawl-budget guide calls a 404 “a strong signal not to crawl that URL again,” which is what you want for pages that are gone.
  • Split subdomains deliberately. If the main domain goes to one place and a subdomain to another, Google says to create a property for the subdomain and migrate it separately.

For a law firm, the second site may carry attorney bios and practice pages with years of inbound links from directories and publications. For a nonprofit merger, it may be campaign pages and donation URLs printed on materials you can’t recall. Both need their own inventory before the first move. When partners or boards are still arguing about the name, my advice is to leave the domain alone until the vote, and use the wait to build those inventories. Which name leads is a brand architecture question, and it should be settled before the website work starts.

Changing platforms or hosts

A new CMS or a move to a CDN can leave every URL the same and still break search. Google has a separate guide for this case, and Change of Address doesn’t apply to it. Most of this section is for your developer. Ask for evidence that each check was run, such as a crawl report or a test against the live firewall.

Hosting and CDN changes

  • Lower your DNS TTL “to a conservative low value (for example, a few hours) at least a week in advance of the move,” so caches pick up the new servers quickly.
  • Check that the new firewall or denial-of-service protection doesn’t block Googlebot, including with its default settings.
  • Expect a short drop in Googlebot’s crawl rate after launch. Per Google’s hosting guide, that is normal and followed by a steady increase over the next few days.
  • Keep the old hosting running until everyone, Googlebot included, is getting the site from the new infrastructure.

CMS and JavaScript frameworks

A move to a JavaScript framework can lose pages without changing a single URL. Google can only discover links that are <a> elements with an href, so menus built from click handlers hide pages from crawlers. It recommends server-side or pre-rendering, partly because “not all bots can run JavaScript.” Client-side apps also need real error responses, or missing pages show up in Search Console as soft 404s. The first test I’d ask for is a crawl of the staging site with JavaScript switched off, which shows what a crawler that can’t render would miss.

Structured data has to survive the move as well. Google reads it from the rendered page, so new templates must output the same markup the old ones did.

Keep AI crawlers able to read the new site

A migration often ships a new robots.txt and new CDN bot rules. Those two files affect whether AI crawlers can still read your pages. None of the six top-ranking migration checklists we read in full for this post mentions AI crawlers.

  • ChatGPT. OAI-SearchBot decides whether you appear in ChatGPT search answers; sites that block it “will not be shown in ChatGPT search answers, though can still appear as navigational links.” GPTBot is for model training and is controlled independently. My default recommendation is to allow OAI-SearchBot and decide on GPTBot as a separate question, since the two do different jobs. OpenAI says it can take “~24 hours” after a robots.txt update for search to adjust, and it recommends allowing requests from its published IP ranges.
  • Claude. Anthropic’s bots honour robots.txt, and an opt-out has to be set “for every subdomain” you block. Anthropic warns that blocking its IP addresses instead may not work reliably, because it stops the bot from reading your robots.txt.
  • Google’s AI features. AI Overviews and AI Mode draw on pages that are indexed and eligible to appear in Search, with “no additional technical requirements.” Google lists making sure crawling is allowed “by any CDN or hosting infrastructure” among its best practices. The Google-Extended token covers Gemini training and grounding and “does not impact a site’s inclusion in Google Search.”

Google’s list of common site-move mistakes starts with noindex or robots.txt blocks that were “only needed for the migration” and never removed. A staging robots.txt that blocks everything can stop Google from crawling and indexing the new site properly and, once OpenAI’s systems adjust, keep it out of ChatGPT search answers. Decide your AI-crawler settings before launch and write them into the production robots.txt. Then check that the CDN’s bot rules match.

In our Q4 2026 index of 262 law firms in four metros, 13 (5%) were named in any of 479 AI answers. We cover the wider picture in getting found in AI search, and our AEO agency service does that work.

How long recovery takes

For a URL-changing move, Google says “for medium-sized websites, it can take a few weeks or more for Google to gradually start showing the new URLs instead of the old ones (and for larger sites, even longer).” It also says rankings may fluctuate during the move and “will settle down over time.”

One study suggests domain moves can take much longer. In a January 2025 Search Engine Journal study, Dan Taylor built a dataset of 892 domain migrations, partly from submissions by SEO practitioners, and measured how long the new domain took to reach the old domain’s organic traffic as estimated by third-party tools. On average it took 523 days. The four fastest took 19 to 33 days, and 17% hadn’t returned to the old level after 1,000 days. The data came from an open call and a tool export, so read the result as a sign of how wide the range is.

Google’s traffic-drop guide suggests widening the Search Console date range to 16 months and comparing year over year, so a seasonal dip doesn’t get blamed on the move.

Website migration SEO checklist

A one-page summary, in the order you’d run it. It adds a few housekeeping items, such as sitemap submission and a baseline export.

Before

  • Settle the final domain. Change of Address can’t be chained straight away.
  • Renew the old domain for at least a year.
  • Check a purchased domain for manual actions and leftover removals.
  • Verify every old and new variant in Search Console, on one Google account, and in Bing Webmaster Tools.
  • Export Search Console performance by page and by query for the old site, as a baseline.
  • For mergers, plan one site at a time and wait for traffic to stabilize before the next.
  • Build the URL inventory and redirect map (see the redesign guide).
  • Lower DNS TTL a week ahead for host or CDN changes.
  • Write the production robots.txt, including AI crawler rules, and test CDN bot settings.
  • Pick a low-traffic window and warn the host about extra crawling.

Launch

  • Redirects live, then Change of Address for each variant.
  • Re-upload the disavow file; update internal links.
  • Submit sitemaps to Google and Bing; send new URLs through IndexNow.
  • Test rendered links, structured data and error pages on each template.

After

  • Keep redirects at least a year; keep the old host until no one uses it.
  • Check each property separately in Search Console, including the Sitemaps report.
  • Compare 16 months, year over year, before calling a drop a loss.

Our free AI visibility snapshot shows whether ChatGPT, Gemini, Perplexity and Google’s AI Overviews name you today, which gives you a baseline before a move. Or book a call to talk the move through.

Sources

, Marketing & Technology Lead, Innovara Studios. Shaya is Marketing & Technology Lead at Innovara Studios. He runs marketing, SEO and AI visibility, and the technology behind the websites and software we build. How we research and write.