Build

The LangChain open source stack provides the building blocks you need to design, test, and ship agents in Python.

Choose your framework

All three frameworks share the same stack, so choose based on how much control you need:

Quickly build agents that can tackle any task.

Customize the building blocks of your agents.

Control every step of your custom agent with low-level orchestration, memory, and human-in-the-loop support.

Connect to model providers, vector stores, retrievers, and other components.

Follow tutorials and conceptual guides for common agent patterns and use cases.

API references, error codes, release notes, and migration guides.

Contribute documentation, code, and integrations to the LangChain ecosystem.