Senior Frontend SWE

Twenty; Washington (District of Columbia); On-site; USD 100,000 - 130,000; Full time

Job summary

A leading technology company in Washington, D.C. seeks an experienced frontend engineer to build critical software solutions. You will develop high-performance React/TypeScript features, implement real-time UI experiences, and collaborate with various teams to enhance user experiences. The ideal candidate has 5-8 years of software development experience, strong knowledge in React and TypeScript, and a passion for impactful projects. Join us in contributing to national security through transformative technology.

Qualifications

• 5–8 years of professional frontend software development experience.
• Strong expertise in React.js and TypeScript with production experience.
• Solid command of modern web fundamentals including JavaScript, HTML, and CSS.
• Experience in building high-performance features at scale.
• Hands-on experience with automated testing frameworks.

Responsibilities

• Build sophisticated React/TypeScript features that operate reliably at scale.
• Implement real-time UI experiences optimizing for speed and clarity.
• Contribute to frontend architecture and design decisions.
• Maintain interactive visualization components like graphs and timelines.
• Participate actively in code reviews to improve quality.

Skills

React.js

TypeScript

JavaScript

HTML

CSS

Automated testing frameworks

State management

Git

Collaborative working

Education

Bachelor's degree in CS/Engineering or equivalent

Tools

D3.js

Neo4j

Vite

Webpack

CI/CD pipelines

Job description

About the Company

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.

What You'll Do

• 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.

Qualifications

Must Have

• 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 Have

• 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).

If this role sounds like you, apply and share with us your interest.

Some positions may require eligibility to obtain a U.S. Government security clearance. Any clearance requirement will be listed in the role description.

Twenty is an equal opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, veteran status, disability, or any other protected status.

If you need a reasonable accommodation during the hiring process, let us know and we will work with you.