Principal Frontend Software Engineer

America is under sustained cyber attack. Our adversaries infiltrate our networks, steal our IP, and degrade the digital infrastructure that modern life runs on. They’ve learned—correctly—that those attacks rarely produce consequences.

America is under sustained cyber attack. Our adversaries infiltrate our networks, steal our IP, and degrade the digital infrastructure that modern life runs on. They’ve learned—correctly—that those attacks rarely produce consequences.

Twenty was founded to change that, by making our adversaries think twice before they attack us. Our vision is American and allied primacy in cyberspace—a future where they cannot contest us, deterrence is assured, and the free world remains secure.

Founded in 2024, Twenty Technologies ((Use the "Apply for this Job" box below).) industrializes offensive cyber operations for the U.S. and its allies. Headquartered in Arlington, Virginia, Twenty has raised $168M from Khosla Ventures, Accel, Caffeinated Capital, Friends & Family Capital, Point
72 Ventures, General Catalyst, and In‑Q‑Tel.

Mission |
On Site | Full Time | U.S. Citizenship Required / No Active Clearance Required

You’ll own the frontend architecture for mission‑critical operator experiences—building high‑performance interfaces that visualize complex cyber operation data in real time. You’ll lead technical direction for UI systems, set the bar for engineering quality, and mentor engineers to move faster with confidence. You’ll partner closely with backend, product, design, and operational stakeholders to ship capabilities that must work reliably in both cloud and on‑premises environments.

You’ll be embedded in a cross‑functional team building capabilities that go directly into operational use — small team, tight feedback loops, real consequences.

• Architect and build sophisticated React/Type Script applications that operate smoothly at scale.
• Design real‑time UI experiences for complex cyber operation data, optimizing for speed and clarity.
• Lead frontend technical architecture and design decisions.
• Build and evolve interactive visualization systems (e.g., graphs, timelines, streaming views).
• Establish reusable frontend architecture patterns and component libraries for consistency and velocity.
• Raise engineering excellence via code review, standards, testing strategy, and performance practices.
• Mentor junior engineers through pairing, feedback, technical coaching, and knowledge transfer.
• Coordinate execution across design, product, backend, and operations to deliver end‑to‑end features.
• Troubleshoot production issues, lead frontend performance investigations, and improve reliability over time.

• You care about building software that has real‑world impact in high‑stakes environments.
• You lead with high standards and high support—clear feedback, strong mentorship, calm execution.
• You think in systems: performance, reliability, accessibility, and maintainability are first‑class concerns.
• You make good tradeoffs under constraints and can explain them crisply to technical and non‑technical partners.
• You enjoy turning complex data into intuitive workflows that help users make decisions quickly.
• You’re comfortable owning ambiguous problems end‑to‑end and driving them to measurable outcomes.
• You default to secure engineering practices and treat trust, safety, and correctness as non‑negotiable.

• You have 8+ years of professional frontend software development experience.
• You have deep expertise building production React.js applications with Type Script.
• You have strong command of modern web fundamentals (JavaScript/Type Script, HTML, CSS).
• You have led frontend technical initiatives and mentored engineers through delivery and growth.
• You have experience…