Faiss

FAISS is Meta's battle-tested vector similarity search library, and it's what you reach for when you need to handle millions or billions of vectors without everything grinding to a halt. It's pure similarity search, no metadata filtering or fancy database features, just blazing fast k-NN powered by C++ with GPU support that can give you 10-100× speedups. The index variety is solid: Flat for exact search, IVF for speed, HNSW for best quality-to-speed ratio, and PQ when memory gets tight. It integrates cleanly with LangChain and LlamaIndex, and with 31,700+ GitHub stars, you're not exactly beta testing here. If you need metadata filtering alongside search, grab Chroma or Pinecone instead. For pure vector retrieval at scale, this is the standard.

Install to Claude Code

npx -y skills add orchestra-research/ai-research-skills --skill faiss --agent claude-code