Senior Backend Engineer, Precision Defense

Get to Know Us Horizon3 is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find and fix and verify exploitable attack vectors before criminals exploit them. Our flagship product, the NodeZeroTM platform, delivers production-safe autonomous pentests and other key assessment operations that scale across the largest internal, external, cloud, and hybrid cloud environments. NodeZero has been adopted by organizations of all sizes, from small educational institutions to government agencies and Global 100 enterprises. It is used by ITOps/SecOps teams, consulting pentesters, and MSSPs and MSPs.  We are a fusion of former U.S. Special Operations cyber operators, startup engineers, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools, false positives resulting in alert fatigue, blind spots, "checkbox” security culture, cybersecurity skills shortage, and the long lead time and expense of hiring outside consultants. Collectively, we are a team of learn it alls, committed to a culture of respect, collaboration, ownership, and results.   ROLE OVERVIEW: As a Senior Backend Engineer on the Precision Defense team, you'll help build the systems that move our customers from reactive security toward proactive, evidence-based defense. The team operates across three closely related areas — Rapid Response, Tripwires/Deception, Security Controls/EDR, and Autonomous Defense — and you'll contribute to backend infrastructure that spans all of them. Depending on where you land within the team, your focus might include: analyzing and surfacing emerging vulnerability intelligence; building and scaling the workflows that help customers identify exposed assets and validate their defenses; deploying and improving deception signals that catch attackers in the act; or producing credible evidence that endpoint detection and response (EDR) controls are working as expected. Across all of these, the common thread is translating attacker-informed findings into measurable defensive outcomes for our customers. This is a high-impact role on a team that owns customer-facing security workflows, supports production incidents, and ships features that directly influence how organizations understand and close their defensive gaps. WHAT YOU’LL DO Responsibilities - Build and maintain backend APIs, ETL pipelines, and data processing systems that power Rapid Response, Tripwires, EDR effectiveness, and Autonomous Defense workflows. - Design and implement GraphQL APIs to facilitate data interactions across product components. - Develop event-driven services and distributed systems that support reliable, scalable security automation. - Collaborate with frontend engineers, attack engineers, and product managers to deliver customer-facing features that communicate security findings clearly and actionably. - Contribute to production reliability: monitoring, alerting, incident response, and debugging across ETL, deployment, and data-propagation workflows. - Support safe, explainable, and reversible security automation — understanding that incorrect behavior in this domain can mean missed detections, noisy alerts, or false confidence for customers. What You'll Bring: - Ability to own and manage concurrent initiatives, demonstrating effective judgment in prioritization and time management. - Driven, self-managed, capable of conceiving and implementing solutions on your own and with a team. - A strong desire to continuously improve and learn new technologies in a fast-paced Agile development environment. - Excellent analytical and problem-solving skills, effective communication, attention to detail, an