LangChain
LangChain is an Observability and AI Monitoring company founded in 2022 and based in San Francisco, United States. It has raised $160M in total funding, most recently a Series B in 2025 at a $1.3B valuation.
Provides the dominant open-source framework for building AI agents plus LangSmith, a commercial platform for tracing, evaluating, and monitoring LLM-powered applications in production. Raised $125M Series B at $1.25B in October 2025; added LangGraph for stateful agents and Deep Agents for autonomous multi-step tasks; $16M revenue in 2025.
LangChain's framework is used by 50K+ companies including Cisco, Replit, and Cloudflare, and LangSmith is becoming the Datadog equivalent for the AI agent stack.
langchain.com ↗·Observability and AI Monitoring·
United States·private 
