Senior Frontend Engineer - Design Systems

Join Mercury as a Senior Frontend Engineer on the Design Systems team, where you'll build and maintain components and patterns that enhance product development, focusing on accessibility and performance. Mercury is built from patterns too. 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. Tending those patterns, and giving everyone at Mercury the means to weave with them, is the work of our Design System team.

• •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.

• •Base salary: $166,600 - $208,300 for US employees.
• •Base salary: CAD 157,400 - 196,800 for Canadian employees.
• •Equity (stock options/RSUs) and benefits.
• •Mercury values diversity & belonging and is proud to be an Equal Employment Opportunity employer.

• •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.
• •First-principles systems thinking that stays oriented to outcomes.
• •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.