LangChain is a platform based on language models designed for building and deploying large-scale applications using RAG (Retrieval Augmented Generation) technology. It encompasses query transformation, hypothesis document embedding (HyDE), routing mechanisms, query construction and indexing strategies, retrieval techniques, and the final generation phase.

Lately, LangChain has implemented the guide for RAG (Retrieval-Augmented Generation), providing users with a detailed tutorial on how to build and deploy large-scale applications using RAG technology with LangChain. Through this guide, users can learn how to leverage LangChain and RAG technology to create their own applications, thereby achieving more efficient information retrieval and generation.