Vector Databases and Vector Search Libraries

Annoy is Spotify's read-optimized approximate-nearest-neighbor library using memory-mapped forests of random-projection trees for static vector collections.

Chroma is an open-source AI data store with collection, embedding, filtering, and vector-query APIs, plus a managed Chroma Cloud service.

Elasticsearch is a distributed search and analytics engine with full-text, dense-vector, sparse-vector, hybrid retrieval, filtering, and learned-reranking capabilities.

FAISS is Meta's library for efficient similarity search and clustering of dense vectors, offering CPU and GPU implementations and a broad family of exact and ANN indexes.

hnswlib is a lightweight C++ and Python implementation of Hierarchical Navigable Small World graphs for approximate nearest-neighbor search with incremental updates.

LanceDB is an open-source, embedded multimodal database built on the Lance columnar format, with vector, full-text, and hybrid search plus a managed cloud.

Marqo is an open-source tensor-search engine for text and images with embedding inference, lexical-vector hybrid search, filtering, reranking, and a managed cloud.

Milvus is a distributed open-source vector database with multiple ANN index types, scalar filtering, hybrid search, GPU support, and horizontal scaling.

OpenSearch is an Apache-2.0 search and analytics suite with k-NN vector indexes, neural and hybrid search pipelines, full-text retrieval, filters, and plugins.

pgvector is a PostgreSQL extension that adds exact and approximate vector similarity search, HNSW and IVFFlat indexes, multiple distance functions, and SQL-native filtering.

ScaNN is Google's vector-similarity search library using quantization, partitioning, and score-aware algorithms for efficient maximum inner-product and nearest-neighbor search.

sqlite-vec is a compact SQLite extension for storing and querying float, int8, and binary vectors without a separate database server.

TiDB Vector Search adds vector columns, distance functions, and HNSW indexes to the distributed SQL database so transactional data and embeddings can be queried together.

turbopuffer is a managed search engine that stores vector and full-text indexes on object storage and exposes filtering, namespaces, and multi-query APIs.

USearch is a single-file vector-search library with HNSW indexes, multiple scalar and binary types, user-defined metrics, persistence, and bindings for several languages.

Vespa is an open-source serving engine that combines structured filtering, lexical matching, nearest-neighbor search, configurable ranking expressions, and distributed document storage.

Zilliz Cloud is the managed Milvus service, adding serverless and dedicated clusters, operational automation, backup, security controls, and integrated data and model services.