What is LangChain?
LangChain is an open-source framework, in Python and JavaScript, for building applications and agents on top of large language models, including chains, tool-calling agents and the LangGraph orchestration layer. The framework is MIT-licensed and free to self-host. The company was incorporated in April 2023 (founded by Harrison Chase) and is headquartered in San Francisco. It separately sells LangSmith, a hosted platform for tracing, evaluation and deployment, on a free-to-start plus usage-based plan.
Read the full overview
Sources checked 27 September 2026: LangChain, GitHub repository, documentation, LangSmith pricing.
LangChainAI Platforms & Generative AIOpen-source framework for building LLM apps and agents
Key capabilities
- Framework: open-source Python/JS libraries for chains, agents and retrieval.
- LangGraph: lower-level orchestration library for stateful, multi-step agents.
- LangSmith (optional, paid beyond free tier): tracing and evaluation, free up to 5,000 traces/month.
- Integrations: community-maintained connectors to model providers, vector stores and data sources.
LangChain can reduce boilerplate for LLM application development, but its value depends on whether the abstractions fit your architecture. License and pricing details are drawn from the LangChain GitHub repository and LangSmith pricing page, checked 27 September 2026.
“Open-source framework for building LLM apps and agents”
Technical details
- Access
- Self-hosted
- Source model
- Open source
- Founded
- 2023
- Pricing model
- Open source
- API
- Available
- Website
- www.langchain.com ↗
- GitHub
- Source repository ↗
What to verify
Start from the users, systems and operating responsibilities the tool needs to support.
- Confirm current features, licensing and support terms.
- Validate deployment, data location and access control.
- Test integrations, exports and recovery workflows.
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