Quivr
Leading#6 in Open sourcehigh confidence
Opinionated RAG 'second brain' you can plug into your apps to store and query your documents (~39k stars).Our read
Why it ranks #6
The existing source records roughly 39k GitHub stars, a strong adoption signal for an opinionated open-source second-brain and RAG backend.Here is the catch
Project direction and documentation have changed substantially across versions
Self-hosting requires database, model, and worker operations
Smaller integration and support ecosystem than LangChain or LlamaIndex
Does this well
Provides more application structure than a low-level RAG library
Open-source backend can be embedded into custom products
Supports multiple model and storage choices
Pricing
Checked by hand on 2026-07-23. Prices in this category change often — if this looks wrong, it probably is.
Key features
Document ingestion and vector storageChat and retrieval APIsConfigurable RAG workflowsSecond-brain knowledge organization
Sources we read
Quick facts
More in this area
The rest of the Open source column.- 1LangChainThe de-facto framework for building RAG and knowledge-base apps — chains, agents, and connectors to every model and vector store. The category's recognized leader (~142k stars).
- 2DifyOpen-source LLM app platform with a built-in knowledge base, document ingestion, and RAG pipeline behind a full UI; the highest-starred option here (~150k stars).
- 3RAGFlowDedicated open-source RAG engine with deep document parsing, knowledge-base management, and a zero-code web UI (~86k stars).
- 4AnythingLLMAll-in-one desktop/self-hosted app that turns your documents into a private chat knowledge base out of the box (~64k stars).
- 5LlamaIndexThe data framework for indexing and querying your private content; the reference toolkit for document-QA knowledge bases (~51k stars).
- 7KhojSelf-hostable AI second brain that searches and chats across your notes, docs, and PDFs (~36k stars).