Site migrations: how to protect your rankings

A site migration, a new domain, a URL restructure, an HTTPS switch, a platform swap, is one of the riskiest things you can do to a working SEO program. Rankings that took years to build can drop within days if the move is not planned. None of this is exotic. It comes down to a redirect map, a pre-launch audit, and patience during the weeks after launch.

What counts as a migration

Not every change carries the same risk. A few common types, roughly from lowest to highest risk:

• URL structure change on the same domain: adding or removing a folder, changing slugs
• Protocol change: HTTP to HTTPS, or subdomain to subdomain
• Platform swap: moving from one CMS or framework to another while keeping URLs the same
• Domain change: moving the whole site to a new domain name
• Site merge or split: combining two domains into one, or breaking one into several

The higher the risk, the more of the checklist below matters. A same-domain URL change still needs a redirect map. A full domain change needs everything on this list, plus extra time to confirm before you commit.

Before you move anything

Do this audit on the live site before a single URL changes.

1. Crawl the current site and export every indexed URL, including ones ranking for long-tail terms you might overlook.
2. Pull current rankings and organic traffic per page from Search Console, so you have a real before-and-after baseline.
3. List your strongest backlinks and which pages they point to. Those pages need redirects that hold, not shortcuts.
4. Record current Core Web Vitals and page speed. A migration is a common moment for performance to quietly regress.
5. Save a copy of structured data and metadata for every template type. It is easy to lose schema markup in a platform swap.

The redirect map is the whole job

If you get one thing right, get this right: every old URL that carried traffic or links needs a 301 redirect to the single closest equivalent new URL. Not a 302, which tells engines the move is temporary. Not a blanket redirect to the homepage, which throws away the relevance the old URL had built. One old URL to one new URL, as close a match as the new site allows.

Watch for redirect chains: an old URL forwarding to another redirect before landing on the final page. Each hop adds delay, and some crawlers give up before the last one. Point every redirect straight at its final destination.

Where a page genuinely has no equivalent anymore, let it 404 or 410 rather than force a redirect to somewhere unrelated. A redirect to an irrelevant page is a worse signal than a clean removal.

What to watch after launch

Expect a dip. Even a well planned migration usually causes a temporary drop in rankings and traffic while search engines recrawl and reassess the new URLs. That is normal for the first few weeks. What is not normal is a dip that does not recover.

• Search Console coverage reports, watching for a spike in 404s or a drop in indexed pages
• Server logs, to confirm crawlers are finding and following the new redirects rather than stalling on old URLs
• Rankings for a fixed list of benchmark keywords, checked weekly rather than daily, since daily checks mostly show noise
• Backlink reports, to catch high-value links still pointing at a dead URL instead of the redirect

Mistakes that turn a dip into a loss

• Internal links left pointing at old URLs instead of updated to the new ones directly
• A staging robots.txt that blocked crawlers during development, still live after launch
• Canonical tags left pointing at the old domain or old URL structure after the move
• hreflang tags not updated for a domain change, breaking international targeting
• No rollback plan, so a serious problem after launch has nowhere to go but forward

A migration does not lose rankings on its own. Missing redirects, broken canonicals, and forgotten robots rules do.

None of this is exotic. If you go into a migration with an export of every URL, a one-to-one redirect map, and a monitoring routine that runs for weeks rather than days, you protect the rankings you already earned instead of hoping they come back.