A search brain for a knowledge platform.
Keyword search was failing users on a platform with millions of documents. We built semantic search with grounded, cited answers — so people find the truth fast and trust what they read.
A library nobody could navigate
The platform held millions of documents, but its keyword search couldn't keep up. Users searched in plain language and got back pages of near-misses; the right answer existed but stayed buried. Search abandonment was the company's top churn driver.
They didn't just want better ranking — they wanted direct answers users could trust, without sacrificing the credibility of citing real sources.
Retrieval you can trust, at scale
We built a retrieval-augmented system where every answer is assembled from real, cited passages — never invented. Hybrid retrieval combines semantic and keyword signals so the system handles both fuzzy questions and exact terminology.
At millions of documents and millions of queries, quality and latency are in constant tension. We treated both as first-class metrics, tuning the index and reranking until grounded answers came back in under half a second.
The system
- An embeddings + hybrid retrieval pipeline over millions of chunked, deduplicated documents.
- A reranking stage that pushes the most relevant passages to the top before generation.
- Grounded answer synthesis with inline citations linking back to the source.
- An incremental indexing system that keeps results fresh as new content lands, with no full re-index.
- A retrieval eval harness scoring relevance and groundedness on a labelled query set.
"Search went from our biggest complaint to our most-loved feature. People tell us it finally 'just knows what they mean' — and they can click through to verify every claim."
Answers, not ten blue links
The system now serves around 3.4 million queries a month with a median response under 400ms. Search-to-answer success — the share of searches that end in the user finding what they needed — more than doubled.
Because every answer cites its sources, trust went up alongside speed: users get a direct response and can verify it in one click.