LangChain
Verified Oct 16, 2026 ActiveMIT-licensed Python/JavaScript framework for building LLM agents, with 1,000+ model and tool integrations
Listed on EffectHub ·
Pricing
- Pricing model
- 100% Free
The framework is MIT-licensed and free, with no seat or usage fees. The company's paid product is LangSmith (separate pricing: Developer $0 for one seat and 5k traces, Plus $39 per seat per month plus usage), which is optional for using the library.
Use tool ↗About LangChain
LangChain is an open-source framework for building agents and LLM applications, giving developers prebuilt agent architectures, middleware hooks and integrations with more than a thousand models, tools and data sources so providers can be swapped without rewriting the app. It ships for Python and JavaScript and, in current versions, runs on the LangGraph runtime for persistence, checkpointing and human-in-the-loop control. The framework itself is MIT-licensed and free; LangChain, Inc. earns revenue from LangSmith, its commercial platform for observability, evaluation and deployment.
- API
- Not confirmed
- Last verified
- Oct 16, 2026
Verified sources
- Framework page FAQ calls LangChain an MIT-licensed open-source library that is free to use; 1,000+ integrations for models, tools and databases; agents run on the LangGraph durable runtime (15 October 2026)langchain.com ↗
- Pricing page covers LangSmith only: Developer $0 per seat (1 seat, 5k base traces), Plus $39 per seat per month then pay as you go, Enterprise custom (15 October 2026)langchain.com ↗
Is LangChain legit?
We don’t label tools safe or unsafe. Below are the records we checked ourselves, each with the date we read it.
- Domain registered
- Dec 3, 2019 (6 years ago)Registry record (RDAP), registrar GoDaddy.com, LLC, looked up Sep 6, 2026
- TLS certificate
- Issued by Google Trust Services, valid until Nov 29, 2026Seen in our own connection to the site on Oct 16, 2026
- Last checked
- Oct 16, 2026The site answered
- On the market since
- 2022The vendor's own material, read by us
- Operated by
- LangChain, Inc., United StatesOur research, card verified Oct 15, 2026
Pros & cons of LangChain
The default starting point for agent development: no other framework matches its integration catalog, documentation volume or hiring-market familiarity. The catch is churn and depth — major versions have repeatedly rewritten core APIs, and once you need observability or managed deployment you are steered toward the paid LangSmith platform.
Pros
- Integrations for 1,000+ models, tools, vector stores and databases
- MIT license with a large contributor community
- LangGraph runtime adds persistence, rewind and human-in-the-loop control
- Python and JavaScript keep parity for most features
Cons
- History of breaking API changes between major versions
- Layers of abstraction complicate debugging versus direct SDK calls
- Production observability and deployment funnel into commercial LangSmith
Best for
- Teams prototyping agents quickly against many models and tools
- Projects that expect to swap LLM providers without rewrites
- Developers who want abundant examples, courses and community answers
Not for
- Minimal services where calling a provider SDK directly is simpler
- Teams unwilling to track breaking changes across major versions
Watch out: Most tutorials in the wild target older LangChain APIs; check the version before copying code, or you will spend the afternoon on import errors.
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