Cybersecurity company Horizon3 has closed a $250 million Series E round, lifting its valuation to $2 billion and more than tripling it in just 14 months. The San Francisco-based startup received renewed support from NightDragon and NEA.
The investment comes at a time when organizations are paying closer attention to how AI can be used both to test and to strengthen digital defenses. Horizon3 has spent six years developing AI systems that safely probe networks for weaknesses in authorized environments, helping enterprises evaluate resilience at scale.
According to the company, its NodeZero platform can test live systems without interrupting operations and continuously scans entire infrastructures rather than relying on limited annual checks. Horizon3 says it has already completed 310,000 production security tests with no disruptions.
The company also reported that it approached $100 million in annual recurring revenue last year, growing 120% year over year. With the new funding, Horizon3 plans to expand internationally, including offices in Amsterdam, Australia, and Singapore, while continuing heavy investment in research and development.
Founded by Snehal Antani and Anthony Pelletier, the company is positioning autonomous penetration testing as a new standard for enterprise security. As AI reshapes digital infrastructure, tools that can validate defenses continuously may become a defining layer of future cyber resilience.
