In-process C++17 library that fuses dense HNSW vector search (usearch) and BM25 full-text retrieval (SQLite FTS5) via Reciprocal Rank Fusion with per-chunk exponential recency decay. Single-writer/concurrent-reader WAL concurrency, no external locking. Pimpl public API. nanobind Python bindings with prebuilt wheels for Linux x86-64 and macOS Apple Silicon.
Cold-start time cut from 14.6 seconds to ~40ms by persisting the HNSW graph to disk. The whole retrieval stack fits in-process — no network hop, no separate service.
at 100k documents