Principal Engineer, Back-End

Horizon3 AI

4d•$213,000 - $273,000•Remote

About The Position

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. We are hiring a Principal Backend Engineer to serve as the Technical Lead. You’ll be responsible for shaping the systems, architecture, and technical direction behind a product that helps customers understand and prioritize what matters most to secure their environments. This role is for a senior individual contributor who leads through technical judgment, cross-functional partnership, and execution. The right candidate will be equally comfortable translating ambiguous product goals into concrete technical roadmaps, writing production code (primarily backend but with an understanding for frontend as well), mentoring other engineers, and influencing decisions across multiple projects and partner teams. Successful candidates will be product minded engineers with an obsession for the details and customer outcomes. As a Principal engineer, you will help shape longer-term technical direction with broader company impact and influence beyond a single domain. In the short-term this role will split time 50/50 between hands-on coding and architectural design. Over time as the team grows, you’ll spend more of your time on design and unblocking the team as they work to deliver best in class experiences for our customers.

Requirements

Deep expertise in software architecture, distributed or service-oriented systems, and the engineering tradeoffs involved in building durable, scalable products. We are at a critical inflection point and are investing heavily in building scalable systems for our continued growth.
Strong technical leadership experience as a senior individual contributor or technical lead, with a track record of leading through influence rather than formal management authority. We are a small team that is growing quickly and you will play a crucial role in our success.
Strong product judgment and the ability to translate business or customer needs into pragmatic technical decisions. If you only care about code, this may not be the right role for you.
Experience working across multiple projects or workstreams at the same time while maintaining clarity on priorities, risks, and execution sequencing. Like most jobs, there will be competing priorities, you’ll help set priorities and communicate tradeoffs.
Proven ability to work effectively with cross-functional partners including Product, Design, Security, peer engineering teams, and senior leadership.
Strong written and verbal communication skills, including the ability to explain technical decisions and tradeoffs to non-technical stakeholders.
A history of mentoring engineers, elevating team performance, and improving engineering craft through design feedback, code reviews, and technical guidance.
Comfort operating in ambiguity and making sound decisions with incomplete information.
Bachelor’s degree in Computer Science, Computer Engineering, or a related field, or equivalent practical experience.
1–4 years of professional software engineering experience.
Experience building backend services using at least one modern language, such as Python, Go, Java, TypeScript, or similar.
Experience working with SQL and at least one relational database in production.
Experience building backend services on a cloud platform (AWS, GCP, or Azure), and familiarity with Docker and containerized applications.
Backend development in one or more of: Go, Rust, Python, Java, or similar
Designing and operating APIs, services, and asynchronous or event-driven systems
Data modeling and persistence layers for product-grade backend systems
Cloud-native application development and deployment patterns
Observability, reliability, and operational best practices for production services
Technical design documents, architectural proposals, and engineering standards that can be adopted by other teams.

Nice To Haves

Experience with PostgreSQL and performance tuning for large datasets.
Experience with graph databases such as Neo4j or interest in learning them.
Experience building or consuming GraphQL backends.
Experience with ETL pipelines and data processing tools (e.g., Airflow-like frameworks, custom ETL jobs, or similar).
Experience with observability stacks (e.g., Datadog, Prometheus, Grafana) and instrumentation of services.
Experience in cybersecurity, vulnerability management, security analytics, security data platforms, or adjacent domains
Experience building products or platforms in vulnerability management, exposure management, security telemetry, or related cybersecurity domains
Familiarity with risk scoring, prioritization systems, or data-intensive backend workflows
Experience partnering closely with product managers to define and sequence an MVP without painting the team into a corner.
Experience helping define technical standards or practices adopted beyond your immediate team.
A track record of shaping technical direction more broadly across an organization, with influence extending beyond a single team or domain.

Responsibilities

Own the end-to-end technical vision for the RBVM and its supporting services, from initial concept through implementation, iteration, and long-term evolution.
Partner with cross functional stakeholders to translate ambiguous product and business goals into concrete technical strategy, architecture, and execution plans for the RBVM team.
Contribute production code, setting the standard for design quality, code quality, and operational rigor.
Lead architectural decisions for scalable backend systems that balance velocity, reliability, maintainability, extensibility, and operability.
Drive execution across multiple concurrent projects and initiatives, identifying risks, dependencies, and tradeoffs early and helping the team sequence work effectively.
Partner closely with Product, Engineering leadership, Design, and adjacent engineering teams to deliver cross-functional initiatives and ensure technical decisions reflect both business context and customer needs.
Communicate complex technical concepts clearly to both technical and non-technical audiences, including leadership stakeholders.
Set and continually raise the technical bar through architecture reviews, code reviews, technical writing, and strong engineering judgment under ambiguity.
Mentor and develop engineers on the team by providing thoughtful feedback, technical coaching, and frameworks that help others do the best work of their careers.
Support hiring by helping attract, interview, and calibrate strong engineering talent as the RBVM organization grows.