Senior Full Stack Engineer (Cybersecurity SaaS)

Location: New York, NY (Hybrid) Salary: $190,000 - $240,000 + competitive equity

Type: Permanent/Full-time

Sector: Cybersecurity/SaaS

The Opportunity

A well-funded, profitable Series B cybersecurity scale-up (c.100 staff) is hiring multiple Senior Full Stack Engineers as it makes a pivotal move from security compliance automation into pure cybersecurity and AI infrastructure for the US federal defense industrial base.

This is a genuine ground-floor moment. The company is cash-flow positive with a healthy runway, and its last two quarters have been its strongest ever, with the majority of new revenue now coming from its federal defense products. It is establishing a new hybrid base in New York, a rare profile for an early-stage, high-growth AI and cybersecurity business outside San Francisco.

You will help build new cybersecurity tooling for American manufacturers and businesses taking on government contracts. (No security clearance required.) We are looking for people genuinely excited by this mission.

What You Will Be Doing

• Develop full-stack features across cutting-edge, experimental products or foundational platform infrastructure
• Work across the full product life cycle, from planning and design through to deployment and optimisation, occasionally stepping into a product-management role
• Build with TypeScript, React, GraphQL and Ruby on Rails, with scope to use modern languages such as Rust or Node.js on new defense-focused products
• Collaborate closely with product, design and engineering peers in a fast-paced, iterative environment
• Provide mentorship to other engineers and help shape team culture

About You

• 3-5 years' commercial software engineering experience: a product-focused generalist and a hacker at heart who ships quickly and takes ownership with minimal oversight
• Senior in terms of impact and ownership, rather than tenure or narrow specialism
• A CS degree from a leading (top-30) programme
• Comfortable across Front End and Back End; specific Ruby experience is not required, as strong engineers pick up the stack quickly
• A track record of excellence and progression: ideally rapid growth and promotion at a strong larger company, or impact at a well-regarded fast-moving startup
• Excited about the cybersecurity mission and building for federal defense contractors

Logistics

• Hybrid in New York City. In-person collaboration starts weekly and is expected to move towards c.3 days/week by year end
• Must be based in NYC or willing to relocate (relocation assistance can be discussed)
• Visa sponsorship is not available
• Immediate need for 2-4 engineers, with further hiring expected through the year

Interview Process

1. 45-minute non-technical conversation (background, motivations, culture fit)
2. Live coding interview (practical data manipulation, not LeetCode)
3. Virtual on-site: code review exercise and a system design discussion
4. Final in-person culture-fit conversation with the hiring lead in New York