LanceDB

Embedded, serverless vector database built on the Lance columnar format (Apache Arrow-based). Runs in-process with no separate server required — data is stored on the local filesystem or object storage (S3, GCS, Azure). Supports vector similarity search, full-text search, SQL filtering, and automatic versioning. Also available as a managed cloud service (LanceDB Cloud). Python package is in 'Alpha' status on PyPI despite being production-used. Backed by pyarrow and pylance (the Lance Rust library, not Microsoft's Python language server).