LLM InfrastructureOpen Source✦ Free Tier

pgvector

PostgreSQL extension for vector similarity search

13,000 stars● Health 75ActiveApp Infrastructure

About

Adds vector similarity search to PostgreSQL. Perfect for teams already on Postgres who don't want to manage a separate vector DB.

Choose pgvector when…

  • You're already on PostgreSQL
  • You want vector search without a separate database
  • SQL queries combined with embedding search are needed

Builder Slot

What knowledge does your AI have?Optional for most stacks

The memory layer — stores and retrieves vector embeddings for RAG and semantic search

Dev Tools
Not applicable
App Infra
Optional
Hybrid
Optional

Other tools in this slot:

Stack Genome Detection

AIchitect's Genome scanner detects pgvector in your project via these signals:

npm packages
pgvector

Integrates with (3)

LangGraphAgent Frameworks

LangGraph retrieval nodes query pgvector via psycopg2 or SQLAlchemy, keeping vector search within the existing Postgres database.

Enterprise RAG with no separate vector DB — LangGraph agents retrieve from the same Postgres instance the rest of the app uses.

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LangChainPipelines & RAG

LangChain's pgvector integration stores and retrieves embeddings from Postgres via the pgvector extension using standard SQL.

RAG without a separate vector database — the app's existing Postgres becomes the retrieval layer.

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LlamaIndexPipelines & RAG

LlamaIndex stores embeddings in Postgres via its PGVectorStore adapter, colocating vector and relational queries.

RAG on top of an existing Postgres database — no separate vector DB, structured and vector queries in the same store.

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Alternatives to consider (4)

Pricing

✦ Free tier available

In 2 stacks

Ruled out by 3 stacks

Indie Hacker / Startup Stack
Don't add a Postgres instance just to prove a concept
Multi-Modal RAG Stack
Storing image embeddings alongside text embeddings needs dedicated vector infrastructure
Research & Synthesis Stack
Corpus-scale semantic search needs a dedicated vector DB, not an extension

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