Horizon3.ai, a cybersecurity company behind the NodeZero autonomous security platform, has secured $100m in its Series D round.
The investment was led by NEA, with additional participation from SignalFire, Craft Ventures and 9Yards Capital. As part of the deal, Lila Tretikov, partner and head of AI strategy at NEA and former deputy CTO of Microsoft, will join Horizon3.ai’s board of directors.
The company specialises in autonomous security, using artificial intelligence to conduct live penetration testing across enterprise systems. Its NodeZero platform operates without human involvement, identifying vulnerabilities by simulating real-world cyberattacks. This allows organisations to test their defences continuously and receive actionable remediation advice based on real threat exposure.
With the new capital, Horizon3.ai plans to scale operations through its partner ecosystem across the Americas, EMEA and APAC, while expanding its product suite into areas such as web application penetration testing, vulnerability management, and precision defence. The company also aims to strengthen its presence within the US federal sector by extending its work with the NSA’s Continuous Autonomous Pentesting programme, advancing FedRAMP High certification, and supporting secret and top-secret workloads.
Horizon3.ai sees itself at the centre of a generational shift in the cybersecurity market, which it estimates to be worth $80bn. The firm believes the future of cybersecurity will be dominated by AI-driven attacks and defences operating at machine speed. Its proprietary system, powered by reinforcement learning and graph reasoning, collects and applies real-world attack data to constantly improve its algorithms.
The company reports strong growth, with over 3,000 organisations globally now using NodeZero, achieving 100%+ year-over-year ARR growth and reaching Rule of 40-positive performance. In one instance, NodeZero autonomously compromised a bank’s security in just four minutes, highlighting its capability to outperform traditional security tools.
Horizon3.ai CEO and co-founder Snehal Antani said, “Over the past four years, we’ve proven that using AI to hack companies isn’t science fiction—it’s real, and it’s delivering measurable results at scale. There are now over 3,000 organizations using NodeZero globally to conduct penetration tests. We’re sustaining 100%+ year-over-year ARR growth, and we are now Rule of 40-positive, which means we’re not just growing—we’re growing efficiently. This raise marks the next chapter in our mission to lead the Autonomous Security category.”
Horizon3.ai CEO and co-founder Snehal Antani added, “Security teams are tired of chasing CVEs, false positives, and compliance checkboxes. They want to find and fix what actually matters, verify it’s resolved, and go home early. The hardest part of the job as a CIO is deciding what not to fix. The second hardest part is proving to the board that your security initiatives are meaningfully reducing risk. NodeZero plays a critical role in reducing your threat exposure over time.”
NEA partner Aaron Jacobson said, “What drew us to Horizon3.ai is the clarity of their mission and the speed at which they’re executing it. They are defining a new security category—autonomous security—and are already the go-to solution for red and blue teams alike. We’re thrilled to lead this round and support the company’s next phase of growth.”
NEA partner and head of AI strategy Lila Tretikov said, “Snehal and the Horizon3.ai team are tackling one of the biggest problems in cybersecurity: automating both sides to ensure maximum defensibility against automated and AI-driven attacks. Their customers love NodeZero, and the team has proven to operate with excellence at scale, which is why Horizon3.ai is transforming how security is done. I’m excited to join the board and help shape this next chapter.”
Horizon3.ai CEO and co-founder Snehal Antani also said, “My old boss used to say, ‘don’t tell me we’re secure, show me, then show me again tomorrow, and again next week, because our environment is always changing and the enemy always has a vote.’”
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