How to preserve SEO during a website migration

Here’s the uncomfortable truth about migrations: search engines don’t rank your website, they rank your URLs. Years of accumulated links, rankings, and trust are attached to specific addresses — and when those addresses change without a forwarding plan, the equity doesn’t move with the files. It just evaporates. The fix isn’t complicated, but it is meticulous: every old URL that mattered needs to point somewhere sensible, permanently.

First, check whether URLs are actually changing

Not every migration touches URLs. Moving to a new host while keeping the same domain and paths is invisible to search engines — no redirect map needed, just the verification steps in the migration runbook. This guide is for the moves that do change addresses: a new domain, a restructured path scheme, a platform switch that renames everything, or several of those at once.

If you have the choice, change one thing at a time. A new host this month and a new URL structure next quarter is two small, diagnosable changes instead of one big ambiguous one.

Build the URL map before anything moves

Inventory the old site’s URLs from more than one source, because each source misses things:

• a full crawl of the live site,
• your analytics’ most-visited pages,
• Search Console’s top-performing pages,
• any pages you know attract links from other sites.

Then build the map: old URL → new URL, page to page. Prioritize ruthlessly — the pages earning traffic and links deserve individual attention; long-tail pages can often follow a pattern rule. Where a page has no equivalent on the new site, redirect it to the closest relevant page, and let genuinely obsolete content return a 404 or 410. That’s honest, and search engines handle it fine.

What you should not do is point everything at the homepage. Google can treat a blanket redirect to an irrelevant destination as a soft 404 — which quietly discards everything the old page had earned.

Use permanent redirects, and keep them clean

Use permanent redirects (HTTP 301 or 308) so search engines transfer signals to the new URLs rather than treating the move as temporary. Implement them server-side — redirect rules at the web server or platform level, not JavaScript.

Keep chains short. If the old URL redirects to an intermediate URL that redirects again, each hop adds latency, and crawlers abandon long chains. Point old URLs directly at their final destination, including the final protocol and host — one hop from http://old.example/page straight to https://www.new.example/new-page.

Update everything you control

Redirects catch visitors from outside; your own site shouldn’t need them. Before launch, update internal links, canonical tags, the XML sitemap, structured data, and hreflang annotations to use the new URLs directly. Then sweep the places people forget: email templates, paid ads, social profiles, and anything hard-coded in apps or feeds.

Cut over and tell Google

Verify both the old and new properties in Search Console before the move. After the redirects go live, submit a sitemap of the new URLs. For a domain change, also use Search Console’s Change of Address tool on the old property — it’s not needed for HTTP-to-HTTPS moves, but for a new domain it explicitly signals what happened.

Spot-check redirects immediately: test your highest-value pages by hand, and run the full map through a crawler or script rather than trusting the rules on faith. One malformed pattern rule can quietly break a thousand URLs.

Monitor, and be patient with the dip

Watch both sides after the move: crawl activity and 404 reports on the old URLs, indexing and impressions on the new ones. Some turbulence in rankings for a few weeks is normal even in a clean migration — the red flags are 404s piling up on URLs that should redirect, or impressions that keep sliding after the first month.

And leave the redirects alone. Google’s site-move documentation recommends keeping them for as long as possible, generally at least a year, because recrawling every link on the web that points at your old URLs takes time. Redirects aren’t scaffolding to tear down after launch week — for your most-linked pages, treat them as permanent infrastructure.

Sources and further reading

• Google Search Central: Site moves with URL changes
• Google Search Central: Redirects and Google Search
• Google Search Console: Change of Address tool
• MDN: Redirections in HTTP