kotaemon is an open-source RAG-based tool and framework for building Q&A apps for knowledge base documents. It can understand multiple document types, including PDF and DOC formats, and provides a web UI, based on Gradio, which allows users to organize and interact with a knowledge base via a chat interface. It has built-in RAG pipelines with a vector store and can be extended with SDKs. kotaemon also cites the source documents in its responses, along with web-based inline previews and a relevance score. For anyone wanting to do a RAG-based document Q&A application, this customizable framework is a very good starting point.