Horizon3.ai
computer & network security · San Francisco, United States · 350 employees · Founded 2019
Horizon3.ai answers the two most important questions in cybersecurity: If someone tried to compromise us, would we hold up? And, how do we withstand the onslaught of AI-powered attacks?
Horizon3.ai’s NodeZero® shifts the advantage from attackers to defenders by giving organizations the power to fight AI with AI. The Proactive Security Platform autonomously tests your defenses at machine speed, safely finds and prioritizes exploitable attack paths, instantly verifies fixes, and drives a continuous loop so you can prove you’re resilient, not just hope you are.
NodeZero, the World’s Best AI Hacker™, was built by an elite team of U.S. cyber veterans and has honed its skills over 225K production-safe tests, more than all manual pentests in history. More than 5,000 organizations including the NSA, CISA, Fortune 100 giants, and major healthcare providers trust Horizon3.ai to prioritize what matters and prove they’re ready for what’s next.
Horizon3.ai has been recognized by Fast Company as one of the World’s Most Innovative Companies in 2026. The company ranked #3 overall on the 2025 Deloitte Technology Fast 500 and was named the #1 cybersecurity company on the Inc. 5000 in 2025. It has also been named to the Fortune Cyber 60 in both 2023 and 2025 and is a two-time Black Unicorn Award winner.
Industry: computer & network security
Headquarters: San Francisco, United States
Approximate size: 350 employees
Founded: 2019
Website: http://www.horizon3.ai
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Specialties: infosec, AI, cybersecurity, offensive security, pentesting, machinelearning, datasecurity, attack surface management
Open positions
- Senior Backend Engineer, Security Controls — San Francisco, United States · On-site · Full-time
- Senior Engineer, Back-End (Security Controls) — San Francisco, United States · On-site · Full-time
- SOC Analyst — San Francisco, United States · On-site · Full-time
- Software Engineer, Back-End (Pentest Platform) — San Francisco, United States · On-site · Full-time
- Staff Defensive Security Software Engineer — San Francisco, United States · On-site · Full-time