Staff Software Engineer (Core UI)

Cobalt Streamworks serves as an AI Proving Ground where organizations can confidently train, test, and outmaneuver adversaries in any environment. Trusted by allied governments, militaries, enterprises, and research institutions worldwide, Cobalt Streamworks enables adaptive, AI-ready defenses that stay ahead of evolving threats. Founded in 2015 by experts from U.S. Cyber Command and MIT Lincoln Laboratory, the platform unifies training, testing, and validation in a realistic, live-fire simulation—helping teams evaluate security investments, optimize performance, and compress cyber readiness cycles from months to days. Why join Cobalt Streamworks? We are an organization that is focused on building our culture and mindfully enhancing our atmosphere every day which is why we have collaborated on an integral value system. Our governing philosophy of being Human Centered is deeply embedded within our value system. We apply this philosophy to every one of our internal team members, external clients, and their customers. How Do We Work? We believe that people are at the center of everything we do. Cobalt Streamworks fosters a culture of continuous learning, curiosity, and professional growth. That belief shows up in action: in-house training, internal and external learning platforms, cyber conferences, industry events, and dedicated time for skill development. Our people are empowered to shape their careers - and it shows. Year over year, Cobalt Streamworks consistently outperforms industry benchmarks in internal mobility, promotions, and total rewards growth. Who Thrives Here? We are a team of innovators, protectors, and problem-solvers. We believe diversity of thought and experience fuels better solutions, and we’re committed to building teams that reflect the communities we serve. Whether you’re remote or office-based, you’ll collaborate with talented colleagues across departments and time zones, united by the mission to create a safer digital world. We invite you to apply today! About the Role Cobalt Streamworks is investing in the craft, consistency, and quality of every interface our customers touch, as well as in the systems that make great UI possible at scale. Our Core UI team owns the foundation the rest of the product is built on: our design system, shared component libraries, frontend architecture, and the partnership between engineering and UX Design. As a Staff Software Engineer on Core UI, you'll be the senior-most technical voice on the team—setting frontend architecture and standards, leading complex UI initiatives end to end, and contributing directly to the systems every product team depends on. You'll partner deeply with UX Designers, Product Managers, and engineers across the organization, and your technical leadership and mentorship will be key to helping the team raise its bar. This is a hands-on technical leadership role, not a people-management one. You set direction through architecture, code, and influence—staying close enough to the work to make the hard calls, unblock difficult problems, and hold a high bar for craft, accessibility, and performance. We're looking for an experienced engineer who wants real ownership of a domain and treats the frontend platform as a product. What You'll Do Set Technical Direction & Architecture Serve as the senior-most technical voice for Cobalt Streamworks's core frontend, owning architecture decisions and the technical roadmap for shared UI systems. Lead major frontend initiatives end to end—from requirements gathering and architecture design through delivery—setting clear goals, priorities, and technical direction. Steward architectural decisions and manage technical and UX debt deliberately, balancing long-term health with delivery needs. Define and enforce frontend technical standards for code health, performance, testing, and documentation. Mentor Design Engineers and frontend engineers, modeling strong craft, collaboration, and pragmatism. Build & Evolve Core UI Systems Design, build, extend, and maintain Cobalt Streamworks's design system (e.g., Monorail) and higher-order component libraries, emphasizing consistency, accessibility, responsiveness, and performance. Contribute directly and deeply to the code, ensuring shared systems stay aligned between design (Figma) and implementation (code, Storybook). Review and curate contributions from other engineers to shared UI libraries, maintaining high standards for UX quality and code health. Bridge UX and Engineering Act as a technical partner to UX Designers—providing feasibility feedback, implementation guidance, and UI engineering insight early in the design process. Define, improve, and automate the workflows that turn design intent into production code efficiently and predictably. Develop prototyping workflows that let UX research gather customer feedback and iterate on designs quickly. Champion Accessibility Lead accessibility (a11y) best practices at the component and system level. Define standards, documentation, and WCAG-aligned guidance that help engineers build access