Site migration

A site migration is any significant change to a site’s URLs, platform, domain, or design made to serve a business goal. Replatforms, consolidations, HTTP-to-HTTPS moves, and redesigns all count, and every one puts rankings at risk, because each alters the signals search and answer engines rely on. The visible layer can look perfect while the structural layer quietly breaks.

How it works

Migrations fail in the structural layer: broken or non-1:1 redirects, lost content parity, changed URL patterns, dropped internal links, and stale canonicals. The discipline that protects a migration is parity plus mapping — every important URL maps 1:1 to its new destination, every page type is validated against the old one, and continuous crawls in staging catch breakage before launch. Prioritize by business value (know your critical pages before scope gets cut) and keep the SEO team involved from planning through 90 days post-launch.

Where it applies

• Ecommerce — replatforms and catalog consolidations where revenue pages must not slip.
• Mergers and rebrands — domain moves that ask search engines to transfer trust to a new address.
• Enterprise — multi-property consolidations where scale multiplies every mistake.

What matters from each seat

• In-house — own the redirect map and parity checklist; they are the migration’s backbone.
• Engineering — validate the new site in staging with real crawls, not just functional QA.
• Brand and leadership — bring SEO in from day zero; the cost of a botched migration is measured in lost revenue, not lost rankings alone.

From the field

Leading search through AutoZone’s move of 5 million-plus URLs onto a mobile-first platform, the discipline that saved it was unglamorous: a 1:1 redirect map, page-type parity checks, and continuous crawls in staging. Rankings recovered within about four weeks of launch — not because the migration got lucky, but because the structural layer was validated before go-live, not after.