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:
langchainThe main entrypoint containing all implementations you need for building applications with LLMs.
langchain-coreCore interfaces and abstractions used across the LangChain ecosystem.
langchain-text-splittersText splitting utilities for document processing.
langchain-mcp-adaptersMake MCP tools available in LangChain and LangGraph applications.
langchain-testsStandard tests suite used to validate LangChain integration package implementations.
langchain-classicLegacy langchain implementations and components.
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.