Senior Frontend SWE

Twenty • Washington, DC

2d

About The Position

At Twenty, we're taking on one of the most critical challenges of our time: defending democracies in the digital age. We develop revolutionary technologies that operate at the intersection of the cyber and electromagnetic domains, where the speed of operations exceeds human sensing and complexity transcends conventional boundaries. Our team doesn't just solve problems – we deliver game-changing outcomes that directly impact national security. We're pragmatic optimists who understand that while our mission of protecting America and its allies is challenging, success is possible.
The Role
You'll be a high-output engineer building mission-critical operator experiences — implementing complex, high-performance interfaces that visualize real-time cyber operation data with speed and precision. You'll contribute meaningfully to frontend architecture and design decisions, own significant features end-to-end, and raise the quality of the codebase around you. You'll work closely with other frontend engineers and cross-functional partners across backend, product, design, and operations to ship capabilities that must work reliably in both cloud and on-premises environments.
Who You Are
You care about building software that has real-world impact in high-stakes environments.
You write clean, precise, and well-tested code and hold yourself to that standard without being asked.
You think carefully about performance, reliability, accessibility, and maintainability as you build.
You make sound tradeoffs under constraints and communicate them clearly to teammates.
You're drawn to complex data problems and enjoy turning them into interfaces that help users act quickly.
You take ownership of your work end-to-end — from design review to production — and take pride in delivering on your commitments.
You default to secure engineering practices and treat trust, safety, and correctness as non-negotiable.

Requirements

• You have 5–8 years of professional frontend software development experience.
• You have strong, production-tested expertise in React.js and TypeScript.
• You have solid command of modern web fundamentals (JavaScript/TypeScript, HTML, CSS).
• You have experience building and shipping features for performance at scale (profiling, optimization, rendering strategies).
• You have hands-on experience with automated testing frameworks (e.g., Vitest, React Testing Library, Playwright or Cypress).
• You have experience with state management patterns and libraries (e.g., Redux, Zustand, or React Query).
• You have experience with modern build tooling (e.g., Vite or Webpack) and CI/CD pipelines.
• You collaborate effectively with product and design to deliver high-quality UX.
• You have strong command of Git in a professional engineering environment, including branch workflows, code review practices, and CI integration.
• You have a Bachelor's degree in CS/Engineering (or equivalent practical experience).

Nice To Haves

• You have experience with complex data visualization (e.g., D3.js, Chart.js, or similar).
• You have exposure to graph databases or graph query patterns (e.g., Neo4j).
• You have experience with real-time streaming data and live system visualization.
• You have worked in defense, security, or other mission-critical domains.
• You have built UI experiences that surface AI/ML outputs in operational workflows.
• You have experience contributing to component libraries or design systems (e.g., Storybook).

Responsibilities

• Build sophisticated React/TypeScript features and components that operate reliably at scale.
• Implement real-time UI experiences for complex cyber operation data, optimizing for speed and clarity.
• Contribute to frontend architecture and design decisions alongside your teammates.
• Build and maintain interactive visualization components (e.g., graphs, timelines, streaming views).
• Write and maintain automated tests across unit, integration, and end-to-end layers.
• Participate actively in code review — giving and receiving feedback that raises the quality bar.
• Identify and address performance issues, technical debt, and reliability gaps proactively.
• Collaborate with design, product, backend, and operations to deliver well-integrated features.
• Support engineers through pairing and practical feedback on their work.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level