Horizon3

AI-Native Proactive Security

Software & SaaS · 501–1,000 employees · San Francisco, CA

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Hiring record

How Horizon3 hires

Strong record. Fewer than a quarter of its open roles have been listed for more than 60 days.

Open now: 72
Over 60 days: 14
Median days open: 14
Reposted roles: 0

Measured nightly from every posting on its own careers page. How we score

About Horizon3

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.

Specialties

cybersecurity
penetrationtesting
AI
purpleteams
infosec
machinelearning
datasecurity
autonomouspentesting
attack surface management
red teams
offensive security
pentesting
security validation
security verification
exploitable vulnerabilities

From Horizon3’s LinkedIn page, matched to the employer’s own website.

Industry: Software & SaaS
Company size: 501–1,000 employees
Headquarters: San Francisco, CA
Founded: 2019

Open jobs at Horizon3

71 open jobs

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Horizon3

How Horizon3 hires

Open jobs at Horizon3

WebApp Offensive Security Software Engineer

Staff Software Engineer, Firewall

Senior IT Engineer, Automation

Senior Backend Engineer, Licensing

Staff Backend Engineer, Licensing

Staff Backend Engineer, MSSP

Senior Backend Engineer, Onboarding and Provisioning

Principal Attack Engineer, AI/LLM

Engineering Manager, Admin Experience

Staff Backend Engineer, Admin Experience

IT Analyst

Engineering Manager, Firewall Defense

Senior WAF Engineer, Autonomous Defense

Staff Product Manager, Agentic Data Platform

Staff Product Manager, Growth

Staff Product Manager, Threat Hunting Experience

Senior Director, Engineering – Proactive Offense

Director of Engineering, Webapp & AI Attack

IT Administrator, Business Applications

Senior Business Applications Engineer