LangChain Raises $300M Series C at a $3B Valuation Led by CapitalG

AI agents are moving out of experiments and into day-to-day work, and building, running and watching them has become a new problem for companies. Picking a model is not enough. Teams need to trace why an agent got something wrong, catch performance slipping in production, and control which tools and data it can reach. LangChain, whose platform targets exactly that, has raised $300 million in a Series C.

From open-source framework to agent engineering platform

LangChain says its mission is to help every company own its intelligence. As agents transform the economy, it says, companies are building domain-specific agents differentiated by their knowledge, data and user experience, and the companies that control them will gain lasting advantages.

The product centers on LangSmith and rests on three pillars. Agent Runtime covers running agents reliably. Deep Agents, LangGraph and LangChain give developers flexibility across models and control over context. LangSmith Agent Server and Sandboxes deploy agents securely at scale in the cloud or a customer’s own environment, and Managed Agents and Fleet run mission-critical agents as managed services. Agent Improvement covers testing and monitoring. Observability and Evaluation show how agents behave and measure quality, and LangSmith Engine, an in-platform agent, finds errors, writes code and prompt fixes and watches production traffic for regressions. Fine-Tuning turns traces into training data for specialized models. Agent Governance gives central control over models, tools and data. LLM and Tool Gateways manage model budgets and fallbacks, protect sensitive data, and govern tool access and authentication.

More than 7,000 organizations already use LangSmith, according to LangChain, from fast-growing startups such as Harvey, Rippling and Listen Labs to Fortune 500 enterprises such as Nvidia, Toyota and Salesforce. Clay uses it to monitor hundreds of millions of agent runs a month. Workday uses it to run and govern agents across the organization, cutting the time to deploy a new agent from five months to under a day. These figures come from the company and have not been independently verified.

A side project that started weeks after ChatGPT

LangChain began within weeks of ChatGPT’s release in late 2022. Harrison Chase, then an engineer at Robust Intelligence, started it as a personal open-source project to fix a gap in large language models: they could not reach live information or take real actions such as web search or API calls. After founding the company with Ankush Gola, he raised a $10 million seed led by Benchmark in April 2023 and a $25 million Series A led by Sequoia in February 2024, at a $200 million valuation.

Valuation more than doubles in a year

LangChain said on Nov. 13 that it raised $300 million at a $3 billion valuation, bringing total funding to $460 million. Existing investor CapitalG led, with significant participation from new investors GIC and DFJ Growth and existing investors IVP and Sapphire Ventures.

New investors also include Salesforce Ventures, Insight Partners, QuantumLight and MongoDB Ventures, and existing investors Sequoia, Amplify and Benchmark returned. LangChain became a unicorn last October with a $125 million Series B at a $1.25 billion valuation, so its valuation has more than doubled in about a year.

Mo Jomaa, a partner at CapitalG, said the shift from experimental LLM applications to production-grade agents is among the most significant in enterprise software today. He said Chase and his team have built a foundational platform for agent engineering and earned the trust of thousands of developers and global enterprises. LangChain will show new LangSmith capabilities at a special release event on Nov. 20.

Competitors

In observability, Braintrust is a leading name. It measures and evaluates how AI models and agents behave in production, and raised an $80 million Series B in February at an $800 million valuation, led by ICONIQ. Langfuse, an open-source LLM observability platform, was acquired by ClickHouse in January, the same day ClickHouse announced a $400 million Series D at a $15 billion valuation.

On the development side, LlamaIndex builds an agent platform around unstructured data and raised a $19 million Series A led by Norwest Venture Partners in March 2025. Temporal, a durable-execution platform that keeps long-running agents going after interruptions, raised $550 million in a Series E in September.