Migrations are the single most reliable way to lose organic traffic, and almost every loss is preventable. The pattern is depressingly consistent: the new site launches, redirects were an afterthought, content silently changed, and three weeks later somebody asks why enquiries stopped.
Migration SEO is a checklist discipline, executed before, during and after launch. I have run this on new builds and replatforms, including a banking site that grew rather than dipped through the transition because the groundwork was done before a page went live.
The migration process
- Pre-launch crawl and full inventory of every ranking URL, with its value
- URL mapping: old to new, one to one, no chains, no lazy homepage redirects
- Content parity checks so pages do not silently lose the text that ranked them
- Staging audit: indexability, canonicals, schema, speed, before go-live
- Launch-day verification and Search Console handling
- Four weeks of monitoring, with a rollback plan and a fix list
The honest expectation: a well-run migration causes a brief wobble, typically one to three weeks, then recovery. A badly run one causes a decline you spend six months undoing.