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Marketplace

Technical SEO recovery after a migration went wrong

Diagnosing and reversing a 58% organic traffic loss for a marketplace, then rebuilding the foundations properly.

Client
Halden Marketplace
Year
2024
Role
Growth · Engineering
Result
Traffic recovered in 14 weeks

The problem

A replatform had shipped with a client-rendered catalogue and no server-side fallback. Two thirds of the index disappeared over six weeks.

What we did

We triaged in the first fortnight, restored crawlability, then spent the following quarter fixing what the migration had papered over.

  • Server-rendered catalogue and canonical strategy
  • Redirect map covering 240k legacy URLs
  • Core Web Vitals brought inside thresholds on mobile

Outcome

Organic sessions returned to pre-migration levels in fourteen weeks and were 22% above baseline by the end of the year.