Hybrid Search for Technical Docs: Why BM25 + Embeddings Beats Either Alone

When users ask domain questions, exact keywords matter (part numbers, acronyms) and meaning matters (synonyms, context). Hybrid search unifies both.

Recipe we like:

1. Index with BM25 for exact matches.
2. Compute embeddings for semantic search.
3. Merge & dedupe results, then re‑rank (e.g., cross‑encoder).
4. Chunk by structure (sections/headings), not fixed tokens.

This approach powered our WeldCraft case study where users found answers 3× faster and support tickets dropped 85%.