Senior Frontend Engineer - Design Systems

What We Do

The Design System team at Mercury builds and maintains the components, patterns, and foundations that everything else at Mercury is built on. This work is crucial because every component, every interaction our customers come to trust, starts with someone deciding how it should go, and making it good enough to be used again and again.

Responsibilities

• Build and maintain the components, patterns, and foundations (tokens, type, color, layout) that Mercury's product is woven from, holding a high bar for accessibility, performance, and pixel-level craft.
• Work hand-in-hand with design partners to bring new patterns from concept to production, tightening the loop between ideation and what actually ships.
• Lead projects that ship new UI patterns to solve real pain points for product teams, helping them build better experiences faster.
• Develop a design system that's as ready for AI as it is for people, applying the technology to create leveraged outcomes.
• Invest in the design system's prototyping experience, shaping the next iteration of how our design function rapidly prototypes, iterates on the product, and explores new concepts.
• Raise the craft and AI fluency of the people around you, through mentorship and clear best practices.

Requirements

• 4+ years of frontend development, with deep experience in React, TypeScript, and modern web technologies.
• Experience building or maintaining a design system or shared component library.
• A thorough command of modern frontend tooling: build systems, CI/CD, and testing.
• High agency, and comfort creating clarity in ambiguous spaces. You take ownership and move without waiting for a defined path.
• First-principles systems thinking that stays oriented to outcomes. You make clear decisions that drive toward results instead of getting stuck in open questions.
• Strong product taste, and an instinct for leverage: the change that makes many teams better, not the one component polished in isolation.
• Hands-on fluency at the intersection of AI and software development: a real command of how emerging AI paradigms are changing the way software gets built, and the ability to turn that into practical leverage, both for the design system itself and for the people who build on it.

Qualifications

• Fluent at the intersection of design systems and AI.
• Comfortable working with a variety of stakeholders including designers, product managers, and engineers.
• Experience with accessibility and performance optimization in web development.
• Ability to communicate complex technical ideas clearly to non-technical stakeholders.

Benefits

• Competitive total rewards package including base salary, equity (stock options/RSUs), and benefits.
• Flexible work arrangements to support work-life balance.
• Continuous learning opportunities and professional development programs.
• Health, dental, and vision insurance coverage.
• Retirement savings plans with company contributions.
• Employee assistance programs for mental health support.

Pay

• US employees: $166,600 - $208,300
• Canadian employees: CAD 157,400 - 196,800

Schedule

• Full-time position.