Staff Software Engineer, Backend MSSP

Horizon3 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.

As a Staff Backend Engineer on the MSSP & TRPM team, you’ll provide hands-on technical leadership for the NodeZero capabilities that enable partners to manage services across many customer environments. You’ll shape architecture for multi-tenant workflows, account hierarchies, delegated administration, client and sub-client management, and asset allocation or deprecation. You’ll guide designs that preserve tenant boundaries and give partners reliable ways to administer their customer relationships. Working across Product and Engineering, you’ll lead complex initiatives while remaining accountable for implementation quality and production outcomes.

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  Set technical direction for partner and multi-tenant platform services, including account hierarchies, tenant isolation, delegated administration, and partner workflows.

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  Lead architecture and implementation of complex capabilities for client and sub-client management, asset allocation or deprecation, and partner administration.

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  Define patterns for secure data boundaries, API design, reliability, observability, and operational readiness.

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  Remain hands-on in complex technical work and help teams make decisions when requirements or tradeoffs are ambiguous.

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  Partner with Product, customer-facing teams, and adjacent engineering groups to align platform capabilities with partner needs.

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  Mentor engineers through design reviews, code reviews, pairing, and technical documentation.

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  Own complex production issues and drive improvements that strengthen service reliability and prevent recurrence.

• Ability to lead broad technical initiatives, establish direction, and build alignment across teams.

• Strong judgment around tenant isolation, security, data integrity, reliability, and customer impact.

• Clear communication and technical writing, including the ability to explain architecture and tradeoffs to both technical and non-technical partners.

• A mentoring mindset and commitment to raising engineering practices across the organization.

• Hands-on ownership of production services, including operational follow-through and continuous improvement.

• Bachelor’s degree in Computer Science, Computer Engineering, or a related field, or equivalent practical experience.

• 8+ years of professional software engineering experience, including deep experience with backend systems and APIs.

• Track record of leading architecture or technical direction for production multi-tenant, platform, or distributed systems.

• Strong understanding of data modeling, service reliability, and security boundaries in customer-facing systems.

• Ability to influence decisions across teams, mentor engineers, and communicate technical tradeoffs clearly.

• Experience building and operating cloud-hosted services and taking ownership of production outcomes.

• Deep experience building backend services in a modern language such as Python, Go, Java, or TypeScript.

• Strong SQL and relational data modeling, API design, and production service-operating experience.

• Experience with cloud-hosted systems and containerized applications such as Docker; familiarity with Kubernetes or a comparable orchestrator.

• Experience with every example technology is not required; depth in relevant areas and the ability to guide sound technical decisions are important.

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Only US persons can interview for this role due to security clearance requirements by our customer(s) and/or vendor(s). Employee must be eligible for and successfully secure a US Federal Security Clearance as a condition of employment.

• Deep experience with MSP/MSSP, reseller, white-label, or partner software platforms.

• Experience with delegated administration, parent/sub-client account models, tenant isolation, RBAC, and audit logs.

• Strong proficiency in Python or Go, SQL/PostgreSQL, AWS, GraphQL, Docker, and Kubernetes.

• Background in cybersecurity or third-party risk management, licensing, entitlements, or compliance-adjacent capabilities.

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

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.

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.