LangChain

Meet LangChain

LangChain is an open-source framework for building applications and agents powered by language models. It provides a shared way to connect models, tools, and data sources, so developers can assemble an agent without writing every integration from scratch. Prebuilt agent patterns offer a starting point, while model-provider integrations let teams adapt their applications as requirements change.

Developers can customize behavior with middleware, add approval steps for human review, and manage longer conversations. Agents run on LangGraph's runtime, which supports persistence and checkpoints for ongoing work. LangChain also integrates with LangSmith for tracing and evaluation, helping teams inspect what an agent did and test changes. It suits developers building assistants, tool-using agents, and other applications that combine model responses with external capabilities.