Marketplace Search Transformation
A large marketplace was losing conversions due to poor search relevance. Users couldn't find what they were looking for, exit rates were climbing, and the gap between catalog quality and search experience had become a significant business problem.
The Challenge
- Search relevance score below industry benchmarks across all major product categories
- No experimentation infrastructure — every change required full deployment with no rollback
- Mixed intent signals — navigational, transactional, and informational queries handled identically
- Cold start problem for long-tail queries with sparse interaction data
The Approach
- 1Ran an intent classification audit across 500K+ search queries to identify the problem distribution
- 2Designed hybrid search architecture combining BM25 lexical retrieval with dense vector embeddings
- 3Built an ML-powered re-ranking layer trained on behavioral signals (clicks, add-to-cart, purchase)
- 4Shipped an experimentation platform enabling 20+ concurrent A/B tests on ranking features
- 5Implemented real-time relevance feedback loop from user interactions
Results
Key Insight
“The biggest lever wasn't the model — it was the feedback loop. Once we connected ranking decisions to purchase signals in near-real-time, the system learned which relevance mistakes were actually costing money.”