Vector Databases & RAG InfrafreeNew

pgvector

Open-source vector similarity search extension for Postgres

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What pgvector does

  • Open-source vector similarity search extension for Postgres
  • HNSW and IVFFlat indexes with exact and approximate search
  • Available on most managed Postgres hosts

pgvector — straight answers

What is pgvector?

pgvector is listed under Vector Databases & RAG Infra, in the Code & Development category on Flocci AI Tools. Open-source vector similarity search extension for Postgres. It is free, with no paid plan attached, and it lives at github.com.

Is pgvector free?

pgvector is listed as fully free — there is no paid tier attached to it in the catalog. That makes it one of the 399 entries on Flocci AI Tools with no upgrade path built in.

What can pgvector do?

pgvector does 3 things the catalog singles out: Open-source vector similarity search extension for postgres; hnsw and ivfflat indexes with exact and approximate search; available on most managed postgres hosts.

What is the best free alternative to pgvector?

LanceDB is the closest free alternative: it sits in the same Vector Databases & RAG Infra sub-category and is free. Microsoft GraphRAG, Milvus and txtai also start free. The full list is on the alternatives page.

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pgvector alternatives

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Qdrant

Vector Databases & RAG Infra
freemium
  • Open-source Rust-based vector database, self-hostable for free with no scale limit
  • Managed free tier cluster (0.5 vCPU/1GB RAM/4GB disk) for prototyping RAG apps with no card required for OSS use
  • Hybrid Cloud option to run managed clusters on your own infrastructure for compliance-sensitive RAG
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Weaviate

Vector Databases & RAG Infra
freemium
  • Free managed cloud plan (100k objects, 1GB memory, 10GB disk) to explore without self-hosting
  • Open-source core project can be self-hosted for free indefinitely, same engine as the managed cloud
  • Built-in hybrid (vector + keyword) search and native embedding/query-agent integrations
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Chroma

Vector Databases & RAG Infra
freemium
  • Fully open-source embedded/self-hosted vector store, the default choice bundled into countless RAG tutorials and frameworks
  • Chroma Cloud managed tier starts with free usage credits, no subscription
  • Simple Python/JS-native API designed to be the easiest on-ramp to RAG for developers
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Microsoft GraphRAG

Vector Databases & RAG Infra
freeNew
  • Builds knowledge graphs and community summaries from private text for RAG
  • Answers global, dataset-wide questions that vector RAG misses
  • Open-source Python library and CLI
  • Works with OpenAI-compatible and local models
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Milvus

Vector Databases & RAG Infra
freeNew
  • Cloud-native Apache-2.0 vector database for large-scale similarity search
  • Runs from a single-file Lite mode to distributed clusters
  • Managed Zilliz Cloud has a separate free tier
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LanceDB

Vector Databases & RAG Infra
freeNew
  • Embedded, developer-friendly retrieval library for multimodal AI
  • Columnar Lance format with vector and full-text search
  • Apache-2.0
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Head-to-head comparisons

pgvector vs Qdrantpgvector vs Weaviatepgvector vs Chromapgvector vs Microsoft GraphRAGpgvector vs Milvuspgvector vs LanceDB