Website migration SEO is the work that keeps your rankings intact when your site changes in a big way: a new domain, a new platform, a new URL structure or a move to HTTPS. Done well, traffic dips briefly and recovers. Done badly, a business can lose a large share of its organic traffic overnight and spend months getting it back.
The difference is almost always preparation. This guide covers the types of migration and how risky each is, how to build the redirect map, what to check on launch day, and how long recovery should take.
What counts as a website migration?
Any change that alters the URLs Google has indexed, or the content and structure behind them. Some are far riskier than others.
| Migration | What changes | Risk |
|---|---|---|
| HTTP to HTTPS | Protocol only | Low, if every URL redirects to its HTTPS version |
| Redesign, same URLs | Templates and layout | Low to medium, depending on content and internal link changes |
| Platform change | CMS, such as WordPress to Shopify or Next.js | Medium to high, because URLs and templates usually change too |
| URL restructure | Paths on the same domain | Medium to high |
| Domain change | The whole address | High |
| Merging sites | Two or more domains into one | High |
Risk adds up. A rebrand that changes the domain, the platform and the URL structure at once is three migrations in one, and when traffic drops it is hard to tell which change caused it. Where you can, change one thing at a time.
What should you do before migrating?
- Save a baseline: Search Console clicks, impressions and positions for your top pages, plus analytics traffic and conversions by landing page
- Crawl the current site and export every URL, with its title, status and canonical
- Export the pages with backlinks from a backlink tool, and the pages with traffic from analytics
- Build the redirect map, described below
- Block the staging site from search engines with a password, not only a noindex tag that might be copied to the live site
- Pick a quiet period for launch, not the week before your busiest season
How do you build a redirect map?
A redirect map is a spreadsheet with every old URL in one column and its new URL in the next. It is the single most important document in any website migration SEO plan.
- List every old URL that has traffic, backlinks or rankings. On a small site, list them all
- Map each one to its closest equivalent on the new site, one to one
- Where a page is being removed, map it to the most relevant remaining page, not automatically to the home page
- Use permanent redirects, 301 or 308, set up on the server
- Avoid chains. Old URLs should go straight to the final new URL, not through an older redirect
- Update internal links on the new site to point directly to new URLs, rather than relying on redirects
Sending every old page to the home page is the most damaging shortcut in migrations. Google tends to treat a redirect to an unrelated page much like a missing page, so the rankings and links those pages had are largely lost.
What should you check on launch day?
- Test a sample of old URLs, including your top pages, and confirm each redirects once to the right new page
- Check that robots.txt is not blocking the site and no noindex tags came over from staging
- Check canonical tags point to the new URLs, not the old domain or staging
- Submit the new XML sitemap in Search Console
- For a domain change, verify the new domain in Search Console and use the Change of Address tool
- Check that analytics and conversion tracking still fire on the new site
Google's Change of Address tool is only for moves between domains or subdomains. It is not needed for HTTP to HTTPS, switching between www and non-www, or changing paths on the same domain.
Should you migrate all at once or in stages?
For small and medium sites, all at once. Google recommends moving all URLs together rather than one section at a time, which also makes problems easier to spot. Very large sites can move in sections, which limits risk but stretches out the period of fluctuation.
How long does a migration take to recover?
Google says to expect temporary ranking fluctuation, and that a small to medium site can take a few weeks for most pages to move, with larger sites taking longer. In our experience, a well-prepared migration usually settles within one to three months. A drop that is still deepening after a month points to something wrong, usually missing redirects, blocked pages or lost content, rather than Google still processing the move.
What should you monitor afterward?
| When | Check |
|---|---|
| Daily, first week | 404 errors in Search Console and server logs, redirects working, top pages indexed |
| Weekly, first two months | Clicks and positions compared with your baseline, page by page |
| Monthly | Backlinks still resolving, the Page indexing report, conversions by landing page |
Compare page by page, not only sitewide totals. A migration can look fine overall while your three most valuable service pages have dropped out.
What about images, PDFs and other files?
They are easy to forget and often carry links. Price lists, brochures and guides saved as PDFs are some of the most linked files on small business sites, and image URLs change whenever a new platform stores media differently. Include them in the crawl and the redirect map. Redirect important PDFs to their new location, or to an HTML page that replaces them. For images that rank in Google Images or are embedded on other sites, redirect the old file URLs where your platform allows it.
How long should you keep redirects?
Google advises keeping them as long as possible, generally at least a year. In practice, keep them permanently. Old links on other sites, bookmarks and printed materials will keep sending people to old URLs for years. For a domain change, keep renewing the old domain so the redirects keep working.
What usually goes wrong?
- Missing redirects for old blog posts, images and PDFs that had links
- Staging noindex or robots.txt rules copied to the live site
- Content cut during the redesign, so pages that ranked lose what made them rank
- Internal links still pointing at old URLs
- Tracking codes missing, so the drop cannot even be measured
If a migration has already gone wrong, recovering lost links is covered in our guide to link reclamation, and the redesign section of the technical SEO audit checklist covers diagnosing a post-launch traffic drop.
The short version
Website migration SEO comes down to a complete redirect map, clean launch checks and page-by-page monitoring against a saved baseline. Change as few things at once as you can, and keep the redirects forever. If you are planning a move and want it handled properly, our technical SEO services include migration planning and launch support.
