LEANN: RAG on Everything — A Complete Guide to Private Local Search

LEANN is a vector database that turns your laptop into a personal RAG engine. It indexes millions of documents while using 97% less storage than traditional solutions — and it does this without losing accuracy. Presented at MLSys 2026, LEANN has quickly grown past 12,800 GitHub stars, and it is easy to see why: full privacy, zero cloud costs, and no telemetry.

How LEANN saves 97% of storage

Traditional vector databases store an embedding vector for every chunk of text. LEANN flips this idea with graph-based selective recomputation: it keeps a compact graph index and computes embeddings on demand only when they are needed. Combined with high-degree preserving pruning, the result is a tiny index that still finds the right documents fast — on a plain laptop, no GPU required.

What you can index

Ecosystem and integrations

LEANN is a drop-in semantic search service with native MCP integration, so it works out of the box with LangChain, LlamaIndex, Ollama, and Claude Code. Because it runs fully offline, your documents never leave your machine — a genuinely private alternative to hosted RAG platforms.

For a step-by-step installation walkthrough, read our tutorial: How to Self-Host LEANN.