Patronus AI, a San Francisco-based startup founded in 2023 by former Meta AI researchers Anand Kannappan and Rebecca Qian, announced a $50 million Series B round led by Greenfield Partners, with participation from Notable Capital, Lightspeed, Datadog, and Samsung. The round brings the company's total funding to $70 million. According to Notable Capital managing director Glenn Solomon, virtually every frontier AI lab and many emerging startups are now customers, and Patronus' revenue has grown 15-fold over the past year, which he described as nearly insatiable demand.
The company builds simulated "digital world models"—replicas of websites and internal systems—in which AI agents are stress-tested after training using reinforcement learning that rewards successful task completion and penalizes errors. Patronus compares its approach to how Waymo trained autonomous cars by building synthetic worlds to test vehicles against rare hazards. "Patronus is really good at spotting the hacks and making sure they are holding the models accountable," Solomon said.
Patronus is currently providing its simulated environments for software engineering and finance, but founder Kannappan said the company wants to expand to harder-to-verify tasks. "We want to be able to actually create the environment in which you can operate an agent that can run for 10 hours or 10 days or 10 weeks," Kannappan said.