Website Migration SEO Checklist

A website migration — new domain, new platform, new design, restructured URLs, or all four at once — is the highest-stakes maneuver in SEO: done right, rankings transfer and life continues; done casually, years of accumulated equity evaporate over a weekend and take quarters to rebuild. The difference is not luck, it's a checklist. Here is that checklist — before, during, and after — built around the one metric that predicts migration success: the percentage of old URLs with a correct, single-hop 301 to their exact new counterpart.

Before: the work that decides the outcome

1. Crawl and inventory the current site — every URL, plus its traffic (analytics), rankings (Search Console) and referring domains (link index). This inventory is the migration's ledger: anything not in it can be lost silently.
2. Build the redirect map: exact counterparts, page to page. Every old URL → its one new equivalent; never everything-to-homepage (a soft-404 signal that transfers nothing, per the redirect rules). Pages with no successor get honest 410s or redirects to the closest genuine relative. Triple-check the rows with backlinks — that's where the equity lives.
3. Freeze scope. The classic disaster is stacking migrations: new domain + new platform + redesigned templates + rewritten content simultaneously, so when traffic drops nobody can isolate why. Migrate structure first, redesign content later — or accept that diagnosis will be archaeology.
4. Stage everything behind a gate — password-protected, unindexable — and pre-verify on staging: templates keep titles/metas/schema, internal links point at new URLs directly (not through redirects), canonicals self-reference the new addresses.
5. Benchmark: export current rankings and traffic by page so "did it work?" has a baseline.

Launch day: the mechanical hour

1. Deploy, then fire the redirect map — server-level 301s, tested immediately on a sample: old URL → 200-status new URL, one hop, including the http/www variants (chains breed here, per the protocol migration guide).
2. Remove the staging gate and verify indexability — the shipped-noindex is the most expensive checkbox in this document.
3. Submit the new sitemap; keep the old sitemap temporarily reachable so crawlers process the moved URLs faster; update robots.txt.
4. Domain changes: use Search Console's Change of Address tool, and verify the new property beforehand.
5. Update what you control externally: profiles, directories, ad destinations, email templates — every link you own pointing at old URLs.

After: the monitored settling

Expect weeks of wobble as recrawl digests the move — rankings dip and recover URL by URL, important pages first; sitewide, a clean migration typically settles within one to two months. Watch daily for the first fortnight: Search Console's coverage report on both properties (old URLs draining, new URLs indexing), 404 reports for redirect-map misses (fix as found — each miss with backlinks is live equity leaking), and traffic-by-page against the benchmark. At month three, run the full audit plus the migration leak-check: sample old URLs for single-hop 301s, crawl for internal links still riding redirects, and flatten any chains that crept in.

Frequently asked questions

How much traffic will I lose during a migration?

A clean structure-only migration: usually a single-digit-percent temporary dip, recovered in weeks. Domain changes run deeper and slower — brand-new domains restart some trust clocks even with perfect redirects. Botched maps, redirect chains and scope-stacked launches are where the 30–60% horror stories come from; every one of them traces to a skipped checklist row.

How long must the redirects stay up?

Effectively forever — external links and bookmarks reference old URLs for years, and each redirect removed re-404s whatever still points there, per the keep-forever rule. Redirect rules cost nothing; keep the map in version control and let it live.

Should I migrate at all if the site works?

Only for reasons that outweigh the risk window: platform genuinely limiting, rebrand decided, HTTPS overdue, or consolidation of properties. "The new design will help SEO" rarely qualifies alone — design refreshes don't need URL changes, and URLs are where migration risk actually lives. When the move is right, the checklist makes it routine — and the equity you're protecting is the years of links that made the site worth migrating (we help build exactly that).