Overview
LangChain is a developer framework for composing applications and agents around language models. It supplies abstractions and integrations for models, tools, retrieval, structured output, memory, and external data sources, with libraries for Python and TypeScript. Developers use it as an application library rather than a hosted chat product. The main repository is MIT licensed and can be installed in a project or extended with integrations. LangChain's surrounding ecosystem includes LangGraph for agent orchestration and LangSmith for tracing, evaluation, and deployment.