Langchain

LangChain is an AI developer tooling company founded in 2022 in San Francisco by Harrison Chase and Ankush Gola. The open-source LangChain framework has become one of the most widely used libraries for building LLM applications, and the company offers LangSmith and LangGraph for observability and agent orchestration.

LangChain is used by hundreds of thousands of developers and thousands of enterprises building AI applications. Customers include Ally, Klarna, and LinkedIn.

The company has raised approximately $260 million, including a $125 million Series B in October 2025 led by IVP at a $1.25 billion valuation, with participation from Sequoia, Benchmark, CapitalG, and others.