// rag · pgvector/pgvector

pgvector

Vector similarity search inside Postgres - store embeddings next to your data

★ 23.3k stars⑂ 1.3k forksNOASSERTIONupdated 2026-10
▦ visual — this project's README ships no embeddable screenshot,
so here's a placeholder. The guide below is complete regardless.
// project facts

Project facts

pgvector is an open-source rag & knowledge project by pgvector (pgvector/pgvector on GitHub). It has 23,276 GitHub stars and 1,341 forks, is released under the NOASSERTION license, and was last updated on GitHub on 8 October 2026.

GitHub stars
23,276
Forks
1,341
License
NOASSERTION
Last updated on GitHub
8 October 2026
Listing
Full install guide
// how it works

How it works

  1. Decide how you will store vectors

    Plan a Postgres table with a vector column sized to your embedding model's dimensions.

  2. Get pgvector for your Postgres

    Clone the repository (or use a Postgres image or managed service that ships it).

  3. Build, install and enable it

    Compile the extension, install it into Postgres, and run CREATE EXTENSION vector in your database.

  4. Run your first similarity query

    Insert a few embeddings, add an index, and query nearest neighbors with the distance operator.

// features

Why people love it

Exact and approximate search

Run exact nearest neighbor queries or speed them up with approximate indexing as your dataset grows.

HNSW indexing

Build HNSW indexes for a strong speed-recall tradeoff on large vector collections.

IVFFlat indexing

Use IVFFlat indexes when you want faster build times and lower memory use than HNSW.

Multiple distance functions

Choose from L2, inner product, cosine, L1, Hamming and Jaccard distances per query.

Flexible vector types

Store single-precision, half-precision, binary and sparse vectors to match your memory budget.

Full Postgres power

Combine vector search with SQL filters, JOINs, transactions and any Postgres client language.

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// run it

Run it yourself

  1. Clone the repository

    Get the source code from GitHub and enter the project directory.

    git clone https://github.com/pgvector/pgvector.git
    cd pgvector
  2. Build and install the extension

    Compile pgvector against your Postgres installation (the README pins the current release branch).

    make
    make install # may need sudo
  3. Enable it and query

    Create the extension in your database, then store and search vectors with plain SQL.

    CREATE EXTENSION vector;
    -- then create a table with a vector column and query with the <-> operator
// use cases

What you can build

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// faq

Questions, answered

Who maintains this project?

It is maintained by the pgvector open-source project, led by Andrew Kane, on GitHub.

Is it free to use?

Yes - pgvector is open source. GitHub lists its license as NOASSERTION, so review the LICENSE file in the repository for the exact terms.

Does it need a paid API key?

No. pgvector itself needs no API key; you only need a way to generate embeddings, which can be a local model or a provider API.

How does it compare to alternatives?

Unlike standalone vector databases such as Qdrant or Milvus, pgvector keeps vectors inside Postgres, so you get transactions, JOINs and one less system to operate - a good default when you already run Postgres.

How do I get started?

Clone the repo, build and install the extension, run CREATE EXTENSION vector, then follow the README's Getting Started section to store and query your first vectors.

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// alternatives

Alternatives in RAG & Knowledge

The most-starred other RAG & Knowledge projects in the LibreAI catalogue — the realistic shortlist if pgvector is not the right fit.

Get pgvector

Free and open — grab the source, star the repo, and start creating.