What is LangChain?

LangChain is the world's most widely adopted open-source framework for building LLM applications and AI agents. It provides a standard architecture for connecting large language models to data sources, APIs, and tools, enabling developers to build sophisticated AI applications without vendor lock-in. With over 223 million monthly downloads and 134,000 GitHub stars, LangChain powers AI teams at Replit, Clay, Harvey, Rippling, Cloudflare, Workday, and Cisco.

LangChain Key Capabilities

LangChain's model provider abstraction layer supports OpenAI, Anthropic, Google Gemini, AWS Bedrock, Hugging Face, and many others. Switching providers typically requires changing one line of code, and application logic doesn't need to change when the underlying model does.

1,000+ Integrations
Community-maintained connectors for vector databases, document loaders, tools, and APIs via langchain-community. This includes modular components including text splitters, retrievers, and output parsers that work as standalone utilities outside full chain architectures.

create_agent (v1.0)
The new create_agent abstraction is the fastest way to build an agent with any model provider. Built on LangGraph runtime, it supports prebuilt and user-defined middleware for step-by-step control and customization.

Middleware Support
Built-in middleware for common use cases including human-in-the-loop approval, summarization, and PII redaction. Custom middleware can hook into various points in the agent loop for fine-grained control.

Standard Content Blocks
Provider-agnostic specification for model outputs supporting reasoning traces, citations, and tool calls across providers. This ensures switching models doesn't break streams, UIs, or memory stores.

The LangChain ecosystem includes three core products:

- LangChain: Open-source framework for building agents quickly with any model provider

- LangGraph: Low-level orchestration framework for custom, stateful multi-agent systems

- LangSmith: Comprehensive platform for observability, evaluation, and deployment

Trusted by Industry Leaders

LangChain is the most popular open-source framework for building AI applications with LLMs, providing the tools and abstractions to connect any model to any data source or API.