Senior Software Engineer - Design Systems

Mercury • San Francisco, NY

1d

About The Position

As a Senior Frontend Engineer on Mercury’s Design Systems team, you will build and maintain the components, patterns, and foundations—including tokens, typography, color, and layout—that underpin Mercury’s product. The role focuses on creating reusable, accessible, high-performance, carefully crafted UI patterns that help product teams build better experiences faster.

You will help develop a design system suited to both people and AI, apply emerging AI capabilities to create practical leverage, and improve the prototyping experience for Mercury’s design function. You will also mentor colleagues and establish best practices that raise the team’s craft and AI fluency.

Requirements

• 7+ years of frontend development experience.
• Deep experience with React, TypeScript, and modern web technologies.
• Experience building or maintaining a design system or shared component library.
• Thorough command of modern frontend tooling, including build systems, CI/CD, and testing.
• High agency and comfort creating clarity in ambiguous situations; takes ownership and moves work forward without waiting for a defined path.
• First-principles systems thinking oriented toward outcomes and clear decisions.
• Strong product taste and an instinct for leverage across teams.
• Hands-on fluency at the intersection of AI and software development, including the ability to apply emerging AI paradigms practically to the design system and its users.

Responsibilities

• Build and maintain components, patterns, and design foundations such as tokens, typography, color, and layout.
• Maintain a high bar for accessibility, performance, and pixel-level craft.
• Lead projects that deliver new UI patterns addressing real pain points for product teams.
• Develop a design system that is ready for AI as well as human use, applying AI to create leveraged outcomes.
• Invest in the design system’s prototyping experience and shape how the design function prototypes, iterates, and explores concepts.
• Mentor others and establish clear best practices to improve the craft and AI fluency of colleagues.

Benefits

• Equity in the form of stock options or RSUs
• Benefits (specific benefits not listed)

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed