LangChain

LangChain is an agent engineering platform and the company behind the open source LangChain, LangGraph and Deep Agents frameworks, along with the commercial LangSmith product. It covers the full lifecycle of building an AI agent: build, test, deploy, monitor, iterate and govern. It is for developers and teams building production agents on any model provider. The open source frameworks range from quick start templates in LangChain, to low level control in LangGraph, to long running autonomous agents in Deep Agents. LangSmith adds step by step tracing, evaluation datasets built from traces, online evals, dashboards and alerts for cost, latency and errors. It also provides deployment infrastructure with Agent Server endpoints, isolated sandboxes for agent generated code, Fleet for building agents in natural language, Engine for detecting production issues and suggesting fixes, and an LLM Gateway for controlling model calls, spend and sensitive data. Deployment can be SaaS, bring your own cloud or self hosted. LangSmith pricing is published in US dollars. Developer is $0 per seat per month for 1 seat with 5,000 base traces per month and community support, then pay as you go. Plus is $39 per seat per month with unlimited seats, 10,000 base traces per month and access to Deployment and Engine, then pay as you go. Enterprise is custom, adding self hosted and hybrid options, custom SSO and a support SLA. Usage beyond included amounts is metered in LangChain Standard Units at $1.00 each. Startups backed by venture capital can apply for up to $10,000 in credits.