Staff Software Engineer, Firewall

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.

We’re hiring a Staff Software Engineer to serve as the hands-on technical lead for the Firewall pod within Precision Defense. NodeZero helps customers understand where Web Application Firewall policies do—and do not—protect them along validated attack paths, then take informed action.

You’ll build and evolve the services and integrations that connect NodeZero with WAF management platforms, assess coverage, and turn validated findings into accurate, safe remediation guidance. You’ll partner with Product, Engineering, AI research, and the Attack team to turn WAF workflows and attack-path evidence into useful, verifiable customer outcomes.

This role is a fit for an engineer who can make an ambiguous problem executable, lead technical direction across a workstream, and stay close to the code and customer impact from design through operation and iteration.

• →

  Own the technical approach for the Web Application Firewall workstream, from problem framing and design through sequencing, delivery, operation, and iteration.

• →

  Design and build reliable integrations with WAF management platforms and their APIs, accounting for differences in vendor policy models and behavior.

• →

  Define correctness checks so recommendations address the validated path while preserving legitimate traffic and service availability.

• →

  Build durable workflows for long-running or resumable operations, with appropriate handling for retries, idempotency, timeouts, and partial failure.

• →

  Where the product supports configuration changes, design safety controls such as tenant-scoped authorization, least privilege, precondition checks, auditability, and validation or recovery paths, including staged rollout and fast rollback for rules that can affect live application traffic.

• →

  Build observability that helps engineers and customers understand what the system assessed, what it recommends, and why.

• →

  Make regular production-code contributions while shaping architecture, leading design and code reviews, and raising the bar for quality, testing, security, and operational readiness.

• →

  Partner with Product and adjacent technical teams to clarify scope, sequence work, manage dependencies, and connect technical decisions to customer outcomes.

• →

  Mentor engineers, lead through influence rather than direct people management, and surface risks and tradeoffs early and clearly in writing.

• Staff-level technical leadership: you can set direction for a workstream, make and explain tradeoffs, and bring other engineers along.

• Strong hands-on software engineering skills, including a record of designing, shipping, and operating production backend systems.

• Product-minded judgment: you can turn a broad goal into a shared problem definition, a practical technical roadmap, and a valuable first release without blocking future evolution.

• A reliability and security mindset: you account for failure modes, correctness, authorization, auditability, and operational needs as part of the design—not as follow-up work.

• The ability to work effectively across Product, Engineering, research, and customer-facing teams, including communicating complex technical decisions to different audiences.

• A collaborative approach to technical leadership: you raise the bar through design, reviews, mentorship, and clear written decisions rather than relying on authority.

• Expert-level proficiency in large-scale Python software development.

• 8+ years experience leading technical work at Staff, Lead, or comparable scope, including architecture, implementation, and cross-team influence.

• Working knowledge of WAF platforms and policy models (i.e. AWS WAF, Cloudflare, F5, Imperva, FortiWeb, or ModSecurity/OWASP CRS), including rules, managed rule groups, and how vendor-specific behavior affects request inspection and blocking decisions.

• Proficiency in other modern backend languages such as Go, or Rust, or a comparable language.

• Experience designing service-oriented systems, APIs, or integrations, including how they behave under failure and partial completion.

• Strong systems-design skills and the ability to make sound tradeoffs across correctness, reliability, security, and maintainability.

• Ability to translate ambiguous product or customer problems into concrete technical plans and deliver outcomes with cross-functional partners.

• Clear technical writing and communication skills.

• Experience in adjacent areas such as API security, bot management, rate limiting, or application security testing (DAST/pentesting), or exposure to network firewall platforms and segmentation.

• Experience integrating with security or infrastructure platforms whose APIs and policy models vary by vendor.

• Experience building security products or systems that assess control coverage, validate attack paths, or produce remediation guidance.

• Experience designing safe automation for changes that can affect customer environments, including authorization, audit, validation, and recovery considerations.

• Familiarity with cloud environments, containerization, and operating services at scale.

• Experience working closely with Product, AI or applied research, or security practitioners to turn domain expertise into customer-facing software.
  

We are a fully remote company, and this job may require up to 10% 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.