Senior UX Designer

Sim Space 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, Sim Space 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 Sim Space? 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. Sim Space 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, Sim Space 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!

Sim Space is seeking a Senior UX Designer II to help shape the future of our application suite. This person will reside in the Boston area, mainly work remotely and at times join the team for meetings in-person.

This role is ideal for a designer who thrives in complex domains, enjoys turning ambiguity into clarity, and can confidently partner with Product Management and Engineering to define and deliver exceptional user experiences.

Success in this role requires strong systems thinking, a customer-centered mindset, and the ability to balance rapid exploration with thoughtful execution. You'll work across challenging enterprise workflows, contribute to our evolving design system, and help drive usability and consistency throughout the application.

• Partner closely with Product Managers and Engineers to discover, define, and deliver valuable customer solutions.

• Translate complex workflows, systems, and technical concepts into intuitive and effective user experiences.

• Use rapid, low-fidelity exploration techniques—including sketches, diagrams, workflows, and prototypes to evaluate ideas, align stakeholders, and accelerate decision-making.

• Design end-to-end experiences through information architecture, user flows, wireframes, prototypes, and high-fidelity designs.

• Conduct user research, usability testing, and design validation activities to inform design decisions.

• Independently lead UX initiatives and drive solutions for complex product challenges.

• Apply established design patterns and contribute to the evolution of our design system to improve consistency, accessibility, and scalability.

• Collaborate with fellow designers through critique, feedback, and shared problem-solving.

• Present design work and rationale clearly to stakeholders, leadership, and cross-functional teams.

• Leverage AI-powered tools and emerging technologies to accelerate research, ideation, design exploration, documentation, and execution.

• You are comfortable working through ambiguity and helping teams find clarity.

• You think in systems, workflows, and outcomes—not just screens.

• You know when to leverage existing design patterns and when to evolve them.

• You use lightweight…