Firn is a high-performance, multi-tenant vector and full-text search engine backed by object storage (S3 / MinIO / R2 / GCS). It is designed as a credible open-source alternative to turbopuffer, proving that a professional-grade tiered storage architecture (RAM → NVMe → S3) is achievable entirely from open-source components. The cost efficiency of S3 with the speed of local RAM. A multi-tenant vector and full-text search engine backed by S3. Built with LanceDB and Foyer for microsecond-scale search latency on top of object storage.