Senior Software Engineer (Frontend)

Twenty is seeking a Senior Frontend Engineer in its Arlington, VA office to help build the next generation of cyber technologies that protect democracies worldwide. We're looking for someone with 8+ years of experience in developing scalable frontend applications, with deep expertise in React.js, TypeScript, and modern web technologies, plus proven leadership experience mentoring engineers and driving technical initiatives. In this role, you'll architect and develop sophisticated, high-performance user interfaces that visualize complex cyber operation data in real-time, lead frontend technical design decisions, mentor junior engineers, and establish engineering best practices across our UI development. You'll join a world-class product and engineering team that delivers mission-critical solutions for U.S. national security, working in both cloud and on-premises environments to build systems that operate at machine speed. If you're passionate about solving complex technical challenges while leading engineering teams and making a direct impact on national security, we want to talk to you.

About the Company

At Twenty, we're taking on one of the most critical challenges of our time: ensuring democracies prevail in the digital age. We develop revolutionary technologies that operate at the intersection of cyber and electromagnetic domains, where the speed and complexity of operations exceeds human cognition. Our team doesn't just solve problems – we deliver game-changing outcomes that directly improve national security. We're pragmatic optimists who know that while our mission of defending America and its allies is challenging, we can succeed.

Role Details

Technical Leadership & Architecture

• Lead the design and architecture of scalable frontend solutions using React and TypeScript that enhance cyber operators' decision-making and response capabilities

• Evaluate and recommend engineering courses of action for new UI features and frontend system enhancements

• Drive technical decision-making for complex data visualization challenges and performance optimizations

• Architect interactive data visualization systems using D3.js, Chart.js, or similar libraries for real-time cyber operation data

• Lead the implementation of responsive, accessible user interfaces that work across devices and screen sizes

• Establish frontend architecture patterns and component libraries for consistent, maintainable code

Team Leadership & Mentorship

• Mentor and provide technical guidance to junior frontend engineers, conducting thorough code reviews and knowledge transfer

• Organize frontend development efforts and assign tasks across engineering teams to optimize workflow and delivery

• Manage project timelines and coordinate cross-functional collaboration with backend, product, design, and operations teams

• Establish and maintain frontend engineering best practices, coding standards, and development processes

• Lead technical discussions and facilitate architectural decision-making sessions for UI/UX implementations

Development & Operations

• Develop high-performance React applications with advanced state management and optimization techniques

• Implement efficient data models and queries using graph databases to support complex relationship mapping in the UI

• Create and maintain comprehensive automated testing suites using Jest, React Testing Library, and Cypress

• Contribute to Go backend services when needed to support full-stack feature development

• Design and implement CI/CD pipelines for frontend applications that enable rapid, secure deployment

• Troubleshoot complex performance issues and lead incident response efforts for frontend systems

• Research and evaluate emerging frontend technologies and frameworks that could enhance our cyber operations capabilities

Qualifications

Technical Skills & Experience

• 8+ years of professional frontend software development experience

• Expert-level proficiency in React.js with demonstrated ability to write clean, efficient, and maintainable component architectures

• Advanced knowledge of modern JavaScript/TypeScript, HTML5, and CSS3

• Proven experience leading frontend technical projects and mentoring junior developers

• Expert experience with frontend build tools, bundlers (Webpack, Vite), and modern development workflows

• Deep knowledge of web accessibility standards (WCAG) and performance optimization techniques

• Extensive experience with frontend testing frameworks (Jest, React Testing Library, Cypress, Playwright)

• Experience with graph databases (Neo4j or similar) and understanding of graph query patterns

• Proficiency with cloud platforms, preferably AWS

• Strong understanding of UX/UI principles and proven collaboration with design teams

• Expert understanding of security best practices, secure coding principles, and frontend security patterns

• Experience with performance profiling, optimization, and scalability engineering for frontend systems

Leadership & Management Skills

• Demonstrated experience mentoring frontend engineers and leading technical teams

• Proven ability to organize development workflows and manage project delivery

• Strong communication skills with ability to explain complex technical concepts to diverse audiences

• Experience conducting thorough code reviews and establishing frontend development standards

• Track record of driving technical decision-making and architectural improvements

Education

• Bachelor's degree in Computer Science, Software Engineering, or related fields, or equivalent practical experience

Security Requirements

• Must be eligible to obtain a U.S. Government security clearance

Distinguishing Qualifications

• Track record of delivering complex technical solutions in defense, security, or mission-critical contexts

• Experience with AI/ML integration in operational systems and visualization of AI outputs

• Background in developing tools for cyber operators, security analysts, or similar high-stakes environments

• Previous experience as a frontend technical lead or engineering manager

• Contributions to open-source projects or technical communities, particularly in React or data visualization

• Experience with real-time data streaming and visualization in production environments

• Experience with large-scale data processing and analysis visualization