Senior Software Engineer - Design Systems

As a Senior Frontend Engineer on the Design Systems team at Mercury, you will build and care for the patterns: the components and foundations that everything else at Mercury is built on. Your work will involve: Building and maintaining 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. Leading projects that ship new UI patterns to solve real pain points for product teams, helping them build better experiences faster. Developing a design system that's as ready for AI as it is for people, applying the technology to create leveraged outcomes. Investing 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. Raising the craft and AI fluency of the people around you, through mentorship and clear best practices. The ideal candidate will have: 7+ 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: 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. The total rewards package at Mercury includes base salary, equity (stock options/RSUs), and benefits. The target new hire base salary ranges for this role are: US employees (any location): $200,700-$250,900 USD Canadian employees (any location): $189,700-$237,100 CAD Job Data by YubHub .