Recovered a 38% traffic drop after a botched JS migration

What was broken.

After migrating to a SPA, organic traffic fell 38% in 3 weeks. Engineering didn't know why and panic was setting in.

What we did.

1. 01Ran log file analysis — Googlebot was hitting 1.8k pages but rendering empty content.
2. 02Implemented SSR on all indexable routes and fixed canonical/hreflang issues.
3. 03Added structured data + breadcrumbs to recover rich results.
4. 04Submitted updated sitemap and monitored re-indexation daily.

What changed.

Traffic recovered above pre-migration levels in 6 weeks. The team now has a pre-deploy SEO checklist that prevents this class of bug forever.