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.

Responsibilities
What You’ll Do

• 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, and high-quality work.
• Strong technical documentation ability to support the development process.
• Effective communication and collaboration with designers, developers, and product managers.
• Ability and interest in mentoring junior and mid-level engineers to foster their growth and development.

Required Education / Experience

• Bachelor's Degree in Computer Science, Computer Engineering, or related field.
• 7+ years of professional software engineering experience using modern object-oriented or functional languages (Python, Java, Go, Scala, C++, TypeScript, etc.).
• Experience building applications on cloud computing platforms such as AWS, Azure, or GCP, using container technologies such as Docker and Kubernetes.
• Expert proficiency in SQL.

What Sets You Apart

• Experience in one or more of the following areas: EDR/endpoint telemetry and control validation; detection engineering and SOC/SIEM workflows; threat detection, deception systems, honeypots, or tripwire-style platforms; vulnerability intelligence and rapid response workflows.
• Familiarity with major EDR platforms (CrowdStrike, SentinelOne, Microsoft Defender) at the telemetry or API level.
• Understands detection logic, alert triage workflows, and how security teams consume and act on findings.
• Comfort translating attack behavior into measurable defensive outcomes.
• Expert proficiency in SQL and experience with relational (PostgreSQL) and graph (Neo4j) database architectures.
• Experience building GraphQL backends.
• Background in event-driven systems, distributed services, observability, and production reliability.

Perks of Horizon3

• Inclusive Team: We value diversity and promote an inclusive culture where everyone can thrive.
• Growth Opportunities: Be part of a dynamic and growing team with numerous career development opportunities.
• Innovative Culture: Work in a collaborative environment that encourages creativity and out-of-the-box thinking.
• Hybrid & Remote Work: We embrace a mix of remote and hybrid work models depending on role and location, including our Chicago office, where some roles require regular in-office presence.
• Competitive Compensation: We offer competitive salary, equity and benefits. Our benefits include health, vision & dental insurance for you and your family, a flexible vacation policy, and generous parental leave.

Compensation And Values
At Horizon3, we believe that our people are our greatest asset, and our compensation philosophy reflects this core value. We are committed to fostering an environment where all employees feel valued, respected, and rewarded for their contributions. Our compensation structure is designed to be fair, competitive, and transparent, ensuring that every team member is recognized and compensated equitably across roles, levels, and locations.

In accordance with various State’s transparency regulations, we provide the following salary range information for this position:

• Base salary range: $170,00 - $235,000 annually. The exact salary will be determined based on the selected candidate’s location, qualifications, experience, and relevant skills.
• Additional compensation: All full-time roles are eligible for an equity package in the form of stock options.

You Belong Here
Horizon3 is not just an equal opportunity employer - we are a community that values diversity, equity, and inclusion as fundamental principles of our culture and success. We are dedicated to fostering a workplace where everyone feels welcome and respected, regardless of race, color, religion, sex, national origin, age, disability, veteran status, sexual orientation, gender identity or expression, genetic information, marital status, or any other legally protected status by law.

Our commitment to diversity and inclusion means we strive to attract, develop, and retain a workforce that reflects the varied communities we serve. We believe that diverse perspectives drive innovation and strengthen our ability to create cutting-edge cybersecurity solutions. At Horizon3, every team member is valued and supported in an environment that encourages personal and professional growth.

We welcome candidates from all backgrounds and experiences, and we encourage all qualified individuals to apply. Come be a part of Horizon3, where your unique contributions are recognized, and your potential is limitless.

Other Duties
Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee. Duties, responsibilities, and activities may change at any time with or without notice.