What is a site migration in SEO?

Site migration, explained

Google's site move guide boils the process down to a few steps. Build a mapping from every old URL to its new URL, using your sitemaps, server logs and analytics to find the ones that matter. Set up server-side permanent redirects (301 or 308) from each old URL to its exact new one. On the new site, give each page a self-referencing canonical, update internal links to the new URLs, and submit new sitemaps in Search Console.

When the domain itself changes, Google's Change of Address tool in Search Console tells it about the move. Google's guidance is to keep redirects as long as possible, generally at least one year, and it warns that a small to medium site can take a few weeks for most pages to move, with larger sites taking longer. Some ranking wobble during that time is normal.

Most migration disasters are self-inflicted. A noindex or robots.txt block from the staging site gets shipped to production. Everything redirects to the new homepage instead of matching pages. Old URLs return 404 because the mapping missed a folder. The new site is slower or thinner than the old one, so it simply doesn't rank as well.

Migrate in the quietest period you can, change as little as possible at once, and crawl both sites before and after.

Why it matters for founders

Startups rebrand and replatform often. A migration done carelessly can wipe out months of organic traffic in a week. One done carefully barely registers.

Example

You move from getacme.io to acme.com. You map 180 old URLs to new ones, add 301s, update canonicals and internal links, submit the new sitemap, and use the Change of Address tool. Traffic moves over within a few weeks.

Common mistakes

• Redirecting all old URLs to the new homepage.
• Shipping a staging noindex or Disallow: / to production.
• Removing redirects after a few months.
• Changing domain, design, URLs and content all at the same time.