Senior Software Engineer - Design Systems at Mercury

The role

As a Senior Frontend Engineer on the Design Systems team, you will build and maintain the foundational components and patterns that power Mercury's product. You will work at the intersection of design systems and AI to create scalable, high-quality UI foundations. Your work will directly enable product teams to build better experiences faster through high-leverage technical decisions.

What you'll do

• Build and maintain core components, tokens, and layout foundations
• Lead projects to ship new UI patterns for product teams
• Develop a design system optimized for both human and AI users
• Enhance the design system's prototyping and iteration experience
• Mentor colleagues to raise craft and AI fluency across the organization
• Ensure high standards for accessibility, performance, and pixel-level craft

What you'll bring

• Seven or more years of frontend development experience with React and TypeScript
• Proven experience building or maintaining shared component libraries and design systems
• Deep command of modern frontend tooling, build systems, and testing
• Strong systems thinking and product taste oriented toward practical outcomes
• Hands-on fluency with AI paradigms and their application in software development

Your impact

You will drive significant efficiency gains across the entire product organization by providing high-leverage UI foundations. By integrating AI into the design system, you will help define the future of how software is built at Mercury. Your leadership will raise the technical bar for frontend engineering and ensure the product remains consistent and high-quality as it scales.