Patronus AI Raises $50M Series B to Stress-Test AI Agents

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Patronus AI, a San Francisco, California company, has raised a $50 million Series B led by Greenfield Partners. Alongside the round, the company unveiled its Digital World Models, a new class of large-scale simulation environments designed to help AI systems train, evaluate, and improve across complex digital workflows.

The round drew participation from existing investors Notable Capital, Lightspeed Venture Partners, Datadog, Samsung, Factorial Capital, Gokul Rajaram, and a group of AI and software executives.

Since launching less than three years ago, Patronus AI has become a recognized name in AI evaluation, simulation infrastructure, and reliability testing for frontier AI systems. The company was founded by researchers and engineers with backgrounds at Meta AI, Amazon AGI, and Google. Its revenue has grown more than 15 times over the past year, a sign of rising demand for tools that help organizations train, evaluate, and deploy increasingly autonomous AI systems. The new funding brings total capital raised to $70 million.

With the fresh capital, Patronus AI plans to expand its research organization, grow its engineering team, and invest in the compute and infrastructure needed to train and run Digital World Models at scale.