Senior Backend Engineer, Growth & MSSP

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.

What You'll Do

• You'll be joining
• Growth & MSSP
• the team that owns the foundational control plane governing what customers can access, what they've purchased, and how they're administered across NodeZero. If the Pentest Platform is the engine, Enterprise Platform is the operating model that determines who gets to use it and how.
• The team's work spans licensing and entitlements, admin experience, provisioning, notifications, MSP/MSSP capabilities, and auditability. These aren't just internal systems - they're the services that directly shape how customers, administrators, and service providers experience NodeZero every day. Getting them right means building for correctness, consistency, and trust across a complex multi-tenant commercial model.

This is a senior individual contributor role. You'll lead through technical judgment, careful system design, and reliable execution - owning significant pieces of platform infrastructure while contributing to a team that balances feature delivery with long-term platform investment and production health.

In this role, you will:

Design and implement backend services that enforce licensing, entitlements, feature access, usage limits, and packaging rules consistently across NodeZero's product, APIs, and partner workflows.

Build and evolve provisioning and onboarding workflows - account setup, entitlement propagation, and auto-provisioning that reliably activates customers without manual intervention.

Develop admin experience infrastructure: user access controls, account settings, parent-child account relationships, and the RBAC/authorization patterns that make multi-tenant administration safe and auditable.

Build MSP/MSSP capabilities - asset allocation, sub-client management, usage visibility, and reporting workflows that let service providers manage multiple customer environments at scale.

Implement audit logging and event history systems that capture administrative, entitlement, usage, and account-level actions for support, compliance, and customer trust.

Develop the notifications platform: usage warnings, consumption alerts, overage notices, product announcements, and other transactional and non-transactional communications.

Operate these services in production - contributing to monitoring, runbooks, incident response, and support workflows for systems customers depend on daily.

Contribute production code that sets the standard for design quality, test coverage, observability, and operational rigor.

Collaborate with adjacent teams - Pentest Data Platform and the Platform Integration Team - to ensure entitlement, access, and account-hierarchy rules are applied consistently wherever NodeZero data is exposed.

What You'll Bring

• Ability to own and manage concurrent initiatives, with strong judgment in prioritization and time management.
• Self-directed and driven - capable of conceiving and implementing solutions independently and as part of a team.
• A strong desire to continuously learn new technologies in a fast-paced Agile environment.
• Excellent analytical and problem-solving skills, with high attention to detail and a high bar for quality - particularly for systems where correctness has commercial and compliance implications.
• Strong technical documentation ability, including design docs, runbooks, and support documentation.
• Effective communication and collaboration across engineering, product, and design.
• Interest in mentoring junior and mid-level engineers.
• Required Education / Experience
• Bachelor's Degree in Computer Science, Computer Engineering, or a related field.
• 7+ years of professional software engineering experience using modern object-oriented or functional languages (Python, Go, TypeScript, Java, Scala, C++, etc.).
• Experience building production applications on cloud platforms (AWS, Azure, GCP) using Docker and Kubernetes.
• Desired Skills: Experience building multi-tenant SaaS platforms with strong tenant isolation - particularly around access controls, data scoping, and account hierarchy.
• Hands-on experience with RBAC, authorization, authentication, or SSO systems, and the patterns that make them consistent and auditable at scale.
• Experience with licensing, subscription, entitlement, usage metering, or billing-adjacent systems - especially where correctness and consistency across services matter.
• Experience designing and building audit log or event history systems with compliance or support requirements in mind.
• Familiarity with provisioning and feature-access patterns - auto-provisioning, feature flags, and staged rollout for commercial SaaS products.
• Experience building admin consoles or customer self-service workflows, including parent-child or multi-org account management.
• Experience with MSP, MSSP, or multi-tenant partner models - asset allocation, sub-account management, and usage/reporting visibility.
• Experience with notifications infrastructure - transactional and non-transactional communications, delivery reliability, and preference management.
• Production reliability experience: observability tooling, on-call ownership, runbook authorship, and incident response for foundational platform services.
• Expert proficiency in SQL and experience with relational database architectures (PostgreSQL); comfort with complex data models involving account hierarchies, usage records, and entitlement state.