LangChain raised $125 million at a $1.25 billion valuation, the company announced on Monday. TechCrunch reported in July that the provider of a popular open source framework for building AI agents was raising fresh funds at a valuation of at least $1 billion. The deal was led by IVP, as we previously reported. New investors CapitalG and Sapphire Ventures joined in, as did existing investors Sequoia, Benchmark, and Amplify.

LangChain began in 2022 as an open source project founded by machine learning engineer Harrison Chase. The startup was an early darling of the AI era, solving problems that made building apps with early-stage LLMs difficult, such as searching the web, calling APIs, and interacting with databases. It became a smash hit project, and Chase launched a startup with a $10 million seed round from Benchmark in April 2023. A week later, Chase raised a $25 million Series A led by Sequoia, reportedly valuing LangChain at $200 million.

As state-of-the-art model makers have added more infrastructure, LangChain has evolved to become a platform for building agents. In addition to announcing its unicorn status, the company launched updates to all of its major products, including its agent builder LangChain, its orchestration and context/memory tool LangGraph, and its testing/observability tool LangSmith. LangChain remains hugely popular among open source devs, with 118,000 stars and 19.4 forks on GitHub.