builder

LangChain

An open agent engineering platform: frameworks plus LangSmith for building and running agents.

agent infrafor developersdeveloper setupopen sourcefree tier

what it is

LangChain makes open-source frameworks for building AI agents and LangSmith, a platform to trace, evaluate, deploy and govern them. Developers use it to build agents with any model and run them in production.

who it's for

Developers and companies building their own AI agents.

how to start

1Read the docs at docs.langchain.com and install the framework for Python or JavaScript.
2Sign up for LangSmith (free Developer plan) to trace and test.
3Build your agent with your model provider's API key.
4Deploy and monitor it in LangSmith.

what you need

Python or JavaScript skills
An LLM API key
A LangSmith account for tracing/deployment

pricing

Developer: $0/seat/month then pay as you go, 1 seat

Plus $39/seat/month then pay as you go; usage in LangChain Standard Units at $1.00/LSU; Enterprise via sales

pricing page ↗checked Oct 10, 2026

key features

Open-source agent frameworks
LangSmith tracing and evals
Deployment
Startup credits

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