CMS migrations are where organic traffic goes to die. We have run fourteen without significant loss.
Phase 1: Pre-migration audit
Crawl the existing site. Build a complete inventory of every indexed URL with traffic, backlinks, and rankings. Identify pages that should not migrate: thin content, duplicates, orphaned URLs.
Phase 2: URL mapping
Every URL mapped to its new equivalent. One-to-one, many-to-one for consolidations, nearest-parent for pages with no equivalent. Thousands of rows, every one reviewed by a human.
Phase 3: Pre-launch validation
Crawl staging. Verify redirects, canonicals, robots.txt, sitemaps, structured data, and Core Web Vitals on the new platform.
Phase 4: Launch and monitoring
Launch on a Tuesday. Monitor hourly for 48 hours. Submit new sitemap. Post-launch crawl within 24 hours. Weekly monitoring for 30 days. A well-executed migration dips 5 to 10 percent and recovers within six weeks.