# LangChain API Reference > Comprehensive API documentation for LangChain Python and JavaScript libraries. > LangChain is a framework for building applications with large language models (LLMs), > including chains, agents, RAG pipelines, and tool-calling workflows. Important notes: - Python packages require Python 3.9+ - JavaScript packages require Node.js 18+ - Most LLM integrations require API keys from the respective providers - All pages are available as markdown by appending `.md` to the URL ## Python Packages - [langchain](https://reference.langchain.com/python/langchain.md): # πŸ¦œοΈπŸ”— LangChain [![PyPI - Version](https://img.shields.io/pypi/v/langchain?label=%20)](https://pypi.org/project/langchain/#history) [![PyPI - Lic... - [langchain_core](https://reference.langchain.com/python/langchain-core.md): # 🦜🍎️ LangChain Core [![PyPI - Version](https://img.shields.io/pypi/v/langchain-core?label=%20)](https://pypi.org/project/langchain-core/#history... - [langchain_mcp_adapters](https://reference.langchain.com/python/langchain-mcp-adapters.md): # LangChain MCP Adapters This library provides a lightweight wrapper that makes [Anthropic Model Context Protocol (MCP)](https://modelcontextprotoc... - [langchain_tests](https://reference.langchain.com/python/langchain-tests.md): # πŸ¦œοΈπŸ”— langchain-tests [![PyPI - Version](https://img.shields.io/pypi/v/langchain-tests?label=%20)](https://pypi.org/project/langchain-tests/#hist... - [langchain_text_splitters](https://reference.langchain.com/python/langchain-text-splitters.md): # πŸ¦œβœ‚οΈ LangChain Text Splitters [![PyPI - Version](https://img.shields.io/pypi/v/langchain-text-splitters?label=%20)](https://pypi.org/project/lang... - [langchain_classic](https://reference.langchain.com/python/langchain-classic.md): # πŸ¦œοΈπŸ”— LangChain Classic [![PyPI - Version](https://img.shields.io/pypi/v/langchain-classic?label=%20)](https://pypi.org/project/langchain-classic... - [langgraph](https://reference.langchain.com/python/langgraph.md): # πŸ¦œπŸ•ΈοΈ LangGraph [![PyPI - Version](https://img.shields.io/pypi/v/langgraph?label=%20)](https://pypi.org/project/langgraph/#history) [![PyPI - Lic... - [langgraph.checkpoint](https://reference.langchain.com/python/langgraph.checkpoint.md): # LangGraph Checkpoint This library defines the base interface for LangGraph checkpointers - [langgraph.store](https://reference.langchain.com/python/langgraph.store.md): # LangGraph Checkpoint This library defines the base interface for LangGraph checkpointers - [langgraph.checkpoint.postgres](https://reference.langchain.com/python/langgraph.checkpoint.postgres.md): # LangGraph Checkpoint Postgres [![PyPI - Version](https://img.shields.io/pypi/v/langgraph-checkpoint-postgres?label=%20)](https://pypi.org/project... - [langgraph.store.postgres](https://reference.langchain.com/python/langgraph.store.postgres.md): # LangGraph Checkpoint Postgres [![PyPI - Version](https://img.shields.io/pypi/v/langgraph-checkpoint-postgres?label=%20)](https://pypi.org/project... - [langgraph.checkpoint.sqlite](https://reference.langchain.com/python/langgraph.checkpoint.sqlite.md): # LangGraph SQLite Checkpoint [![PyPI - Version](https://img.shields.io/pypi/v/langgraph-checkpoint-sqlite?label=%20)](https://pypi.org/project/lan... - [langgraph.prebuilt](https://reference.langchain.com/python/langgraph.prebuilt.md): # LangGraph Prebuilt This library defines high-level APIs for creating and executing LangGraph agents and tools - [langgraph_cli](https://reference.langchain.com/python/langgraph-cli.md): # LangGraph CLI [![PyPI - Version](https://img.shields.io/pypi/v/langgraph-cli?label=%20)](https://pypi.org/project/langgraph-cli/#history) [![PyPI... - [langgraph_sdk](https://reference.langchain.com/python/langgraph-sdk.md): # LangGraph Python SDK This repository contains the Python SDK for interacting with the LangSmith Deployment REST API - [langgraph_supervisor](https://reference.langchain.com/python/langgraph-supervisor.md): # πŸ€– LangGraph Multi-Agent Supervisor > **Note**: We now recommend using the **supervisor pattern directly via tools** rather than this library for... - [langgraph_swarm](https://reference.langchain.com/python/langgraph-swarm.md): # πŸ€– LangGraph Multi-Agent Swarm A Python library for creating swarm-style multi-agent systems using [LangGraph](https://github.com/langchain-ai/la... - [deepagents](https://reference.langchain.com/python/deepagents.md): # πŸ§ πŸ€– Deep Agents [![PyPI - Version](https://img.shields.io/pypi/v/deepagents?label=%20)](https://pypi.org/project/deepagents/#history) [![PyPI - ... - [deepagents_acp](https://reference.langchain.com/python/deepagents-acp.md): # Deep Agents ACP integration This directory contains an [Agent Client Protocol (ACP)](https://agentclientprotocol.com/overview/introduction) conne... - [deepagents_code](https://reference.langchain.com/python/deepagents-code.md): # πŸ§ πŸ€– Deep Agents Code [![PyPI - Version](https://img.shields.io/pypi/v/deepagents-code?label=%20)](https://pypi.org/project/deepagents-code/#hist... - [langchain_amazon_nova](https://reference.langchain.com/python/langchain-amazon-nova.md): # `langchain-amazon-nova` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-amazon-nova?label=%20)](https://pypi.org/project/langchain-ama... - [langchain_anthropic](https://reference.langchain.com/python/langchain-anthropic.md): # `langchain-anthropic` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-anthropic?label=%20)](https://pypi.org/project/langchain-anthrop... - [langchain_astradb](https://reference.langchain.com/python/langchain-astradb.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-astradb?label=%20)](https://pypi.org/project/langchain-astradb/#history) [![PyPI - Licen... - [langchain_aws](https://reference.langchain.com/python/langchain-aws.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-aws?label=%20)](https://pypi.org/project/langchain-aws/#history) [![PyPI - License](http... - [langchain_azure_dynamic_sessions](https://reference.langchain.com/python/langchain-azure-dynamic-sessions.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-azure-dynamic-sessions?label=%20)](https://pypi.org/project/langchain-azure-dynamic-sess... - [langchain_cerebras](https://reference.langchain.com/python/langchain-cerebras.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-cerebras?label=%20)](https://pypi.org/project/langchain-cerebras/#history) [![PyPI - Lic... - [langchain_chroma](https://reference.langchain.com/python/langchain-chroma.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-chroma?label=%20)](https://pypi.org/project/langchain-chroma/#history) [![PyPI - License... - [langchain_cohere](https://reference.langchain.com/python/langchain-cohere.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-cohere?label=%20)](https://pypi.org/project/langchain-cohere/#history) [![PyPI - License... - [langchain_community](https://reference.langchain.com/python/langchain-community.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-community?label=%20)](https://pypi.org/project/langchain-community/#history) [![PyPI - L... - [langchain_db2](https://reference.langchain.com/python/langchain-db2.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-db2?label=%20)](https://pypi.org/project/langchain-db2/#history) [![PyPI - License](http... - [langchain_deepseek](https://reference.langchain.com/python/langchain-deepseek.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-deepseek?label=%20)](https://pypi.org/project/langchain-deepseek/#history) [![PyPI - Lic... - [langchain_elasticsearch](https://reference.langchain.com/python/langchain-elasticsearch.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-elasticsearch?label=%20)](https://pypi.org/project/langchain-elasticsearch/#history) [![... - [langchain_exa](https://reference.langchain.com/python/langchain-exa.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-exa?label=%20)](https://pypi.org/project/langchain-exa/#history) [![PyPI - License](http... - [langchain_fireworks](https://reference.langchain.com/python/langchain-fireworks.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-fireworks?label=%20)](https://pypi.org/project/langchain-fireworks/#history) [![PyPI - L... - [langchain_google_community](https://reference.langchain.com/python/langchain-google-community.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-google-community?label=%20)](https://pypi.org/project/langchain-google-community/#histor... - [langchain_google_genai](https://reference.langchain.com/python/langchain-google-genai.md): # `langchain-google-genai` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-google-genai?label=%20)](https://pypi.org/project/langchain-g... - [langchain_google_vertexai](https://reference.langchain.com/python/langchain-google-vertexai.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-google-vertexai?label=%20)](https://pypi.org/project/langchain-google-vertexai/#history)... - [langchain_groq](https://reference.langchain.com/python/langchain-groq.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-groq?label=%20)](https://pypi.org/project/langchain-groq/#history) [![PyPI - License](ht... - [langchain_huggingface](https://reference.langchain.com/python/langchain-huggingface.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-huggingface?label=%20)](https://pypi.org/project/langchain-huggingface/#history) [![PyPI... - [langchain_ibm](https://reference.langchain.com/python/langchain-ibm.md): # `langchain-ibm` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-ibm?label=%20)](https://pypi.org/project/langchain-ibm/#history) [![Py... - [langchain_litellm](https://reference.langchain.com/python/langchain-litellm.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-litellm?label=%20)](https://pypi.org/project/langchain-litellm/#history) [![PyPI - Licen... - [langchain_milvus](https://reference.langchain.com/python/langchain-milvus.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-milvus?label=%20)](https://pypi.org/project/langchain-milvus/#history) [![PyPI - License... - [langchain_mistralai](https://reference.langchain.com/python/langchain-mistralai.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-mistralai?label=%20)](https://pypi.org/project/langchain-mistralai/#history) [![PyPI - L... - [langchain_neo4j](https://reference.langchain.com/python/langchain-neo4j.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-neo4j?label=%20)](https://pypi.org/project/langchain-neo4j/#history) [![PyPI - License](... - [langchain_nomic](https://reference.langchain.com/python/langchain-nomic.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-nomic?label=%20)](https://pypi.org/project/langchain-nomic/#history) [![PyPI - License](... - [langchain_nvidia_ai_endpoints](https://reference.langchain.com/python/langchain-nvidia-ai-endpoints.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-nvidia-ai-endpoints?label=%20)](https://pypi.org/project/langchain-nvidia-ai-endpoints/#... - [langchain_ollama](https://reference.langchain.com/python/langchain-ollama.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-ollama?label=%20)](https://pypi.org/project/langchain-ollama/#history) [![PyPI - License... - [langchain_openai](https://reference.langchain.com/python/langchain-openai.md): # `langchain-openai` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-openai?label=%20)](https://pypi.org/project/langchain-openai/#histo... - [langchain_openrouter](https://reference.langchain.com/python/langchain-openrouter.md): # `langchain-openrouter` [![PyPI - Version](https://img.shields.io/pypi/v/langchain-openrouter?label=%20)](https://pypi.org/project/langchain-openr... - [langchain_parallel](https://reference.langchain.com/python/langchain-parallel.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-parallel?label=%20)](https://pypi.org/project/langchain-parallel/#history) [![PyPI - Lic... - [langchain_perplexity](https://reference.langchain.com/python/langchain-perplexity.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-perplexity?label=%20)](https://pypi.org/project/langchain-perplexity/#history) [![PyPI -... - [langchain_pinecone](https://reference.langchain.com/python/langchain-pinecone.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-pinecone?label=%20)](https://pypi.org/project/langchain-pinecone/#history) [![PyPI - Lic... - [langchain_postgres](https://reference.langchain.com/python/langchain-postgres.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-postgres?label=%20)](https://pypi.org/project/langchain-postgres/#history) [![PyPI - Lic... - [langchain_qdrant](https://reference.langchain.com/python/langchain-qdrant.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-qdrant?label=%20)](https://pypi.org/project/langchain-qdrant/#history) [![PyPI - License... - [langchain_redis](https://reference.langchain.com/python/langchain-redis.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-redis?label=%20)](https://pypi.org/project/langchain-redis/#history) [![PyPI - License](... - [langchain_sema4](https://reference.langchain.com/python/langchain-sema4.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-sema4?label=%20)](https://pypi.org/project/langchain-sema4/#history) [![PyPI - License](... - [langchain_snowflake](https://reference.langchain.com/python/langchain-snowflake.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-snowflake?label=%20)](https://pypi.org/project/langchain-snowflake/#history) [![PyPI - L... - [langchain_sqlserver](https://reference.langchain.com/python/langchain-sqlserver.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-sqlserver?label=%20)](https://pypi.org/project/langchain-sqlserver/#history) [![PyPI - L... - [langchain_tavily](https://reference.langchain.com/python/langchain-tavily.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-tavily?label=%20)](https://pypi.org/project/langchain-tavily/#history) [![PyPI - License... - [langchain_together](https://reference.langchain.com/python/langchain-together.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-together?label=%20)](https://pypi.org/project/langchain-together/#history) [![PyPI - Lic... - [langchain_unstructured](https://reference.langchain.com/python/langchain-unstructured.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-unstructured?label=%20)](https://pypi.org/project/langchain-unstructured/#history) [![Py... - [langchain_upstage](https://reference.langchain.com/python/langchain-upstage.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-upstage?label=%20)](https://pypi.org/project/langchain-upstage/#history) [![PyPI - Licen... - [langchain_weaviate](https://reference.langchain.com/python/langchain-weaviate.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-weaviate?label=%20)](https://pypi.org/project/langchain-weaviate/#history) [![PyPI - Lic... - [langchain_xai](https://reference.langchain.com/python/langchain-xai.md): [![PyPI - Version](https://img.shields.io/pypi/v/langchain-xai?label=%20)](https://pypi.org/project/langchain-xai/#history) [![PyPI - License](http... - [langsmith](https://reference.langchain.com/python/langsmith.md): # LangSmith Client SDK [![Release Notes](https://img.shields.io/github/release/langchain-ai/langsmith-sdk?logo=python)](https://github.com/langchai... ## JavaScript Packages - [langchain](https://reference.langchain.com/javascript/langchain.md): # πŸ¦œοΈπŸ”— LangChain.js ![npm](https://img.shields.io/npm/dm/langchain) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https:/... - [@langchain/core](https://reference.langchain.com/javascript/langchain-core.md): # 🦜🍎️ @langchain/core ![npm](https://img.shields.io/npm/dm/@langchain/core) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)... - [@langchain/textsplitters](https://reference.langchain.com/javascript/langchain-textsplitters.md): # πŸ¦œβœ‚οΈ @langchain/textsplitters This package contains various implementations of LangChain.js text splitters, most commonly used as part of retriev... - [@langchain/mcp-adapters](https://reference.langchain.com/javascript/langchain-mcp-adapters.md): # LangChain.js MCP Adapters [![npm version](https://img.shields.io/npm/v/@langchain/mcp-adapters.svg)](https://www.npmjs.com/package/@langchain/mcp... - [@langchain/react](https://reference.langchain.com/javascript/langchain-react.md): # @langchain/react React SDK for building AI-powered applications with [Deep Agents](https://docs.langchain.com/oss/javascript/deepagents/overview)... - [@langchain/vue](https://reference.langchain.com/javascript/langchain-vue.md): # @langchain/vue Vue SDK for building AI-powered applications with [Deep Agents](https://docs.langchain.com/oss/javascript/deepagents/overview), [L... - [@langchain/svelte](https://reference.langchain.com/javascript/langchain-svelte.md): # @langchain/svelte Svelte 5 SDK for [Deep Agents](https://docs.langchain.com/oss/javascript/deepagents/overview), [LangChain](https://docs.langcha... - [@langchain/angular](https://reference.langchain.com/javascript/langchain-angular.md): # @langchain/angular Angular SDK for building AI-powered applications with [Deep Agents](https://docs.langchain.com/oss/javascript/deepagents/overv... - [@langchain/langgraph-sdk](https://reference.langchain.com/javascript/langchain-langgraph-sdk.md): # LangGraph JS/TS SDK This repository contains the JS/TS SDK for interacting with the LangGraph REST API - [@langchain/langgraph-checkpoint](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint.md): # @langchain/langgraph-checkpoint This library defines the base interface for [LangGraph.js](https://github.com/langchain-ai/langgraphjs) checkpoin... - [@langchain/langgraph-checkpoint-mongodb](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint-mongodb.md): # @langchain/langgraph-checkpoint-mongodb Implementation of a [LangGraph.js](https://github.com/langchain-ai/langgraphjs) CheckpointSaver that uses... - [@langchain/langgraph-checkpoint-postgres](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint-postgres.md): # @langchain/langgraph-checkpoint-postgres Implementation of a [LangGraph.js](https://github.com/langchain-ai/langgraphjs) CheckpointSaver that use... - [@langchain/langgraph-checkpoint-redis](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint-redis.md): # @langchain/langgraph-checkpoint-redis Redis checkpoint and store implementation for LangGraph - [@langchain/langgraph-checkpoint-sqlite](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint-sqlite.md): # @langchain/langgraph-checkpoint-sqlite Implementation of a [LangGraph.js](https://github.com/langchain-ai/langgraphjs) CheckpointSaver that uses ... - [@langchain/langgraph-checkpoint-validation](https://reference.langchain.com/javascript/langchain-langgraph-checkpoint-validation.md): # @langchain/langgraph-checkpoint-validation The checkpointer validation tool is used to validate that custom checkpointer implementations conform ... - [@langchain/langgraph-api](https://reference.langchain.com/javascript/langchain-langgraph-api.md): # LangGraph.js API In-memory implementation of the LangGraph.js API - [@langchain/langgraph-cli](https://reference.langchain.com/javascript/langchain-langgraph-cli.md): # LangGraph.js CLI The official command-line interface for LangGraph.js, providing tools to create, develop, and deploy LangGraph.js applications - [@langchain/langgraph-cua](https://reference.langchain.com/javascript/langchain-langgraph-cua.md): # πŸ€– LangGraph.js Computer Use Agent (CUA) > [!TIP] > Looking for the Python version? [Check out the repo here](https://github.com/langchain-ai/lan... - [@langchain/langgraph-supervisor](https://reference.langchain.com/javascript/langchain-langgraph-supervisor.md): # πŸ€– LangGraph Multi-Agent Supervisor A JavaScript library for creating hierarchical multi-agent systems using [LangGraph](https://github.com/langc... - [@langchain/langgraph-swarm](https://reference.langchain.com/javascript/langchain-langgraph-swarm.md): # πŸ€– LangGraph Multi-Agent Swarm A JavaScript library for creating swarm-style multi-agent systems using [LangGraph](https://github.com/langchain-a... - [deepagents](https://reference.langchain.com/javascript/deepagents.md):