SEO Migration

Definition

SEO migration is a high-risk technical SEO activity because changes that break the signals Google has indexed for a site — canonical URLs, link equity paths, structured data, meta tags — can cause significant ranking drops. Common types of SEO migrations: (1) **Domain migration** — moving content from one domain to another (rebranding, acquiring a new domain, consolidating multiple domains). Requires 301 redirects from every URL on the old domain to the equivalent URL on the new domain. Google must discover the redirects, crawl the new URLs, and update its index — a process that can take weeks to months. (2) **CMS migration** — moving from one CMS to another (WordPress to Next.js, Drupal to Contentful). URL structures may change, requiring redirect mapping. Structured data implementation may change. Meta tag templates change. (3) **HTTP to HTTPS migration** — covered in the https-seo glossary term. (4) **URL restructure** — changing URL patterns within the same domain (adding/removing subdirectories, changing slug patterns). Requires redirect mapping from every old URL to its new equivalent. (5) **Site redesign** — changing page templates, navigation structure, content organisation. May change internal link structure, meta tag templates, and structured data implementation. Redesigns are high-risk because multiple signals change simultaneously. **Pre-migration requirements**: (a) Crawl the existing site and export all URLs; (b) Map every old URL to its new URL equivalent; (c) Prepare 301 redirects for every URL being changed; (d) Audit existing structured data, meta tags, and internal links to replicate correctly in the new implementation; (e) Set up Google Search Console for the new domain/URL structure before migration. **Post-migration monitoring**: compare organic traffic and rankings before/after migration (30-day windows); monitor GSC Coverage for 404 errors indicating missing redirects; check GSC Performance for query-level ranking drops indicating specific pages affected.

Why it matters for SEO

SEO migrations are one of the most common causes of significant, sudden organic traffic drops in the SEO industry. A domain migration without proper 301 redirects can lose 40–80% of organic traffic within weeks. A CMS migration that changes URL structures without a redirect map can achieve similar results. The key risk: Google has indexed the old URLs, built its understanding of the site\'s authority around those URLs, and indexed the link equity flowing to those URLs. Cutting that off (via URL changes without redirects) requires Google to re-discover the new URLs, re-crawl them, and rebuild its understanding — a process that can take months even with correct redirect implementation. A well-executed migration with comprehensive redirects typically sees organic traffic recover within 3–6 months; poorly executed migrations can take 12–18 months to recover, if at all.

How DeepSEOAnalysis checks this

The audit checks post-migration health indicators: redirect completeness (crawling all discovered URLs and checking for 404 responses on URLs that should be redirected); redirect chain depth (migrations that resulted in chains of redirects rather than direct redirects); canonical tag accuracy (new URLs declaring correct self-referential canonicals); meta tag migration completeness (meta titles and descriptions present and not using default CMS templates); structured data migration (Article, FAQPage, LocalBusiness structured data correctly implemented in the new CMS); and internal link update completeness (internal links updated to point to the new canonical URLs rather than the old URLs that are now behind redirects).

Useful tools and resources

• Free post-migration SEO audit