FastGPT

FastGPT is a knowledge-based platform built on the LLMs, offers a comprehensive suite of out-of-the-box capabilities such as data processing, RAG retrieval, and visual AI workflow orchestration, letting you easily develop and deploy complex question-answering systems without the need for extensive setup or configuration. Maintained by labring on GitHub, where it has earned 29,581 stars from the community.

It's actively developed around nextjs, openai, llm, and is a solid reference for anyone building with these tools.