Yes — pgvector is open-source under PostgreSQL. You can self-host for free.

How many open-source vector databases options are there?

There are many, but we've curated the 6 best picks based on production-readiness, license safety, maintenance velocity, and community size.

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Vector databases · open-source ranking

Best Open-Source Vector Databases in 2026

Q: What is the best open-source vector databases?

Our top pick is pgvector: Postgres extension for vector search. The default if you already use Supabase, Neon, or Postgres. Production-ready.

Every RAG app needs a vector database. The question in 2026 is no longer "Pinecone or build your own" — it's which open-source option fits your stack. pgvector wins if you already use Postgres. Qdrant leads on pure-vector performance. Chroma is the easiest start. Weaviate has the best hybrid (keyword + vector) search. Below are the honest picks for production AI apps.

#1 Pick — Best if you use Postgres

pgvector

Postgres extension for vector search. The default if you already use Supabase, Neon, or Postgres. Production-ready.

github.com/pgvector/pgvector

All 6 ranked

pgvector

Best if you use PostgresPostgreSQLSelf-host~13k

Postgres extension for vector search. The default if you already use Supabase, Neon, or Postgres. Production-ready.

github.com/pgvector/pgvector

Qdrant

Best raw performanceApache-2.0Self-host~22k

Rust-based dedicated vector DB. Best raw performance + filtering. Hosted cloud or self-host with one Docker container.

github.com/qdrant/qdrant

Chroma

Easiest to startApache-2.0Self-host~16k

Easiest start. `pip install chromadb` and you have a vector DB. Best for prototyping + sub-100k embeddings.

github.com/chroma-core/chroma

Weaviate

Best hybrid searchBSD-3-ClauseSelf-host~12k

Hybrid search (vector + keyword + filters). Best when search relevance matters more than pure semantic similarity.

github.com/weaviate/weaviate

Milvus

Best at billion+ scaleApache-2.0Self-host~30k

Largest-scale vector DB. Billion+ vectors. Pick this when you outgrow others. Heavy to operate but unmatched at scale.

github.com/milvus-io/milvus

LanceDB

Embedded / on-deviceApache-2.0Self-host~5k

Embedded vector DB (think SQLite for vectors). Zero infra. Best for on-device or edge-deployed AI.

github.com/lancedb/lancedb

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