LangChain reference

Welcome to the LangChain package reference documentation!

Most users will primarily interact with the main langchain package, which provides the complete set of implementations for building LLM applications. The packages below form the foundation of the LangChain ecosystem, each serving a specific purpose in the architecture:

• langchain

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  The main entrypoint containing all implementations you need for building applications with LLMs.

  Reference

• langchain-core

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  Core interfaces and abstractions used across the LangChain ecosystem.

  Reference

• langchain-text-splitters

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  Text splitting utilities for document processing.

  Reference

• langchain-mcp-adapters

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  Make MCP tools available in LangChain and LangGraph applications.

  Reference

• langchain-tests

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  Standard tests suite used to validate LangChain integration package implementations.

  Reference

• langchain-classic

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  Legacy langchain implementations and components.

  Reference

Integration Packages

Looking for integrations with specific providers and services? Check out the integrations reference for packages that connect with popular LLM providers, vector stores, tools, and other services.