Staff Backend Engineer, Internal

What You’ll Bring

• The ability to own multiple complex initiatives, make sound prioritization decisions, and keep work moving across teams with competing dependencies.
• A self-driven, hands-on approach: you can set direction, make progress through ambiguity, and deliver independently while bringing others along, and you say plainly what is and isn't yet guaranteed.
• A reliability mindset for distributed work: you design for retries, partial failure, and recovery, and methodically diagnose asynchronous systems and production issues.
• Strong technical judgment: you weigh performance, correctness, scalability, operability, and maintainability, and clearly explain tradeoffs and their customer or business impact.
• A track record of influencing technical decisions beyond your immediate team and building alignment across engineering and product partners.
• A commitment to developing other engineers through mentorship, thoughtful reviews, and clear technical guidance.
• Excellent analytical and problem-solving skills, clear communication, and attention to detail.
• Strong technical writing for architecture proposals, design docs, runbooks, and API documentation.
• A strong desire to keep learning new technologies in a fast-paced Agile environment.

Required Education / Experience

• Bachelor's Degree in Computer Science, Computer Engineering, or a related field.
• 8+ years of professional software engineering experience using modern object-oriented or functional languages (Python, Java, Go, Scala, C++, TypeScript, etc.).
• Demonstrated technical leadership on high-complexity backend or data-platform initiatives, including setting direction and delivering work across multiple teams or stakeholders.
• Experience designing, building, and operating production data-processing, ETL, or distributed task-processing systems at scale.
• Hands-on experience with backend APIs, relational data models, and SQL in production systems.
• Experience building applications on cloud computing platforms such as AWS, Azure, or GCP, and using container technologies such as Docker.

Horizon3.ai is a fast-growing, remote cybersecurity company dedicated to the mission of enabling organizations to proactively find, 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 IT Ops/SecOps teams, consulting pentesters, and MSSPs and MSPs.

We are a fusion of former U.S. Special Operations cyber operators, startup engineers & operators, and formerly frustrated cybersecurity practitioners. We're committed to helping solve our common security problems: ineffective security tools and 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.

• Deep experience shaping cross-team backend architecture and establishing practices that improve the quality, reliability, or operability of systems beyond your own team.
• You can sit down with a slow query, explain-analyze it, and come back with a rewrite that changes the runtime by an order of magnitude, and you've set that bar enough times that it's routine on this team, not heroic.
• You've built ETL that ran unattended against messy, real-world source data and didn't silently drop records or stall without alerting, and you've held it up under wildly uneven per-tenant scale.
• You're comfortable being the connective tissue between backend, frontend, and data pipelines, and you set the patterns for the seam where they meet.
• Fluency with the modern Python toolchain this team runs on, including SQLAlchemy, versioned migrations, uv, ruff, mypy, and pytest, and the inclination to raise those standards rather than just meet them.
• Experience designing durable, observable data workflows with orchestration engines such as Temporal, Prefect, Airflow, Celery, or similar.
• Deep experience with GraphQL backends and with graph databases such as Neo4j.
• A track record of owning observability for what you ship, metrics, alerting, and dashboards (for example Datadog, Prometheus, or OpenTelemetry), so the team watches it in production, not you personally, and you raise that operational bar for others.
• Systems engineering experience with attack-path data, relational datasets, and the services that make complex security results useful to customers.
• Experience deploying containerized services, including in Kubernetes-based production environments.
• Experience building platform capabilities or internal tooling that multiple engineering teams rely on.
• Experience in cybersecurity or with internal attack, identity, privilege-escalation, and vulnerability data, with enough of an offensive-security frame of reference to collaborate fluently with attack engineers, no glossary required.

Travel Required

We are a fully remote company, and this job may require up to 5% of travel to be successful.

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.

Application Note

In any materials you submit, you may redact or remove age-identifying information such as age, date of birth, or dates of school attendance or graduation. You will not be penalized for redacting or removing this information.

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: $229,000 - $270,000 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.

Perks of Horizon3 http://Horizon3.ai

• 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.