LangChain

LangChain is a San Francisco–based software company building the developer platform and open-source frameworks used to create AI agents. It was launched in October 2022 as an open source project by Harrison Chase while he was working at machine learning startup Robust Intelligence, and incorporated as LangChain, Inc. in April 2023.

The company offers a comprehensive platform spanning the entire agent engineering lifecycle, enabling teams to build and ship reliable agents to production. Beyond its original framework, it has launched LangGraph (a production runtime for controlling complex agent systems), LangSmith (a commercial AI observability, evaluation, and deployment platform with a no-code agent builder), and most recently Deep Agents, an agent harness for autonomous, long-horizon tasks.

LangChain works with 35% of the Fortune 500, has crossed 1 billion open source downloads, and ingests over 1 billion events per day on LangSmith. It is headquartered in San Francisco with offices in New York, Boston, and Amsterdam, and cites customers including Zip, Vanta, Klarna, Workday, LinkedIn, and Cloudflare. In October 2025 it raised a $125M Series B led by IVP at a $1.25B valuation, with backers including Sequoia, Benchmark, CapitalG, Sapphire Ventures, ServiceNow Ventures, Workday Ventures, Cisco Investments, Datadog, Databricks, and Frontline.

As a company whose mission is to make intelligent agents ubiquitous, LangChain is directly relevant to innovation in AI agent engineering—its tools are foundational to how developers move from prototypes to production-ready AI agents.