Cybersecurity startup Horizon3 has raised $250 million in Series E funding at a valuation exceeding $2 billion, more than tripling its $650 million valuation from roughly a year earlier. Returning investors NightDragon and NEA co-led the oversubscribed round, which included seven new investors and five existing backers.
The San Francisco-based company develops NodeZero, an autonomous penetration-testing platform that safely attacks authorised enterprise systems to identify exploitable weaknesses. Horizon3 plans to use the funding for international expansion, research and development, sales, marketing and its partner network.
NodeZero Tests Live Systems Continuously
NodeZero examines networks, cloud environments and software applications from an attacker’s perspective. It identifies working attack paths, provides evidence of their effect and guides customers through remediation before verifying that the fixes work.
Chief revenue officer Matt Hartley said the platform can test production systems without interrupting operations. He added that companies can examine their full infrastructure weekly or monthly instead of hiring consultants to sample a small portion during an annual assessment.
Horizon3 said it has completed 310,000 production security tests without causing a disruption. The company describes its technology as an autonomous AI hacker because it can execute penetration tests without requiring a human operator to direct each action.
Revenue and Customer Base Continue Growing
Horizon3 approached $100 million in annual recurring revenue last year after recording 120% year-over-year growth, according to Hartley. The company now serves approximately 7,200 to 7,300 customers, ranging from managed service providers supporting small businesses to Fortune 10 companies.
Founders Snehal Antani and Anthony Pillitiere met while serving at the US Joint Special Operations Command. They created Horizon3 in 2019 after seeing how staffing and budget limits made frequent security testing difficult.
The company has invested approximately $100 million in research and development to make its automated testing predictable and controllable. Its official funding announcement said enterprises increasingly need evidence that their security controls can withstand real attacks as AI gives attackers new ways to find and exploit vulnerabilities.
Funding Supports International Expansion
Horizon3 established its European headquarters in Amsterdam in June 2026 and is expanding into Australia and Singapore. The company is also building a larger international partner network while maintaining its research spending.
Strategic investors include Singapore’s EDBI, defence contractor SAIC and Qualcomm. Horizon3 estimates that the market for its services is worth tens of billions of dollars as companies shift from occasional human-led testing towards continuous validation.
Hartley said traditional penetration-testing firms would continue to operate, but customer expectations were changing. Companies increasingly want to test entire environments repeatedly and measure whether security improvements are reducing their exposure over time, according to TechCrunch.
Featured image credits: Magnific.com
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