FastGPT

FastGPT is an open-source platform for building question-answering systems over your own documents: data ingestion and chunking, retrieval, and a visual workflow builder sit together, and its selling point is that the retrieval is inspectable — you can tune how documents are split and test what comes back. Its repository reports roughly 29,800 stars, and the site now markets it as an enterprise agent builder rather than only RAG.

It suits a team that has documents to answer from and wants to self-host the whole stack next to its own models, including Chinese-language deployments where the documentation and community are deepest. It suits less well a team that mainly wants general-purpose agent features, because the product grew out of retrieval and the broader agent tooling is thinner than the platforms it is usually compared with.

Not verified: the repository reports a non-standard licence, so the terms — particularly around offering it as a service — should be read before any commercial deployment. No documents were ingested and no retrieval was run, so answer quality is untested. The site advertises many documentation languages where the entry's own note called the docs Chinese-first; that note is now out of date.