The most popular framework for building AI agents and LLM apps
LangChain is the most widely adopted framework for building LLM-powered applications and AI agents. It provides a composable architecture where developers can chain together LLM calls, prompts, memory systems, and external tools to create sophisticated AI workflows. The framework supports all major LLM providers (OpenAI, Anthropic, Google, open-source models) and offers pre-built integrations with hundreds of data sources, vector databases, and APIs. LangChain's agent module enables developers to build autonomous AI systems that can reason about tasks, select appropriate tools, and execute multi-step workflows. With LangSmith for debugging and LangGraph for complex agent architectures, the ecosystem provides everything needed to go from prototype to production. Available in Python and JavaScript/TypeScript.
Core framework is free. LangSmith has free and paid tiers.
LangChain v0.3
LangChain was released to the public, marking its official debut in the AI landscape.
LangChain v0.3
Our team verified LangChain's pricing, features, and capabilities to ensure accuracy.
Install via pip (Python) or npm (JavaScript)
Set up your LLM provider API keys
Build chains with prompts, LLMs, and tools
Create agents with tool access and memory
Deploy with LangServe or your own infrastructure
Best For
Developers building custom AI agents and LLM applications
Free Trial
Free (open source)
Mobile App
No (developer framework)
API Access
Full programmatic access
Team Features
LangSmith team workspaces
Last Updated
2026-03-01
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