This Design System Designer role sits within Mercari's Design System team, supporting the creation, evolution, and governance of the design system across multiple product teams. The role blends UI craft, systems thinking, and collaboration with designers, engineers, and brand partners.
What you'll do
- Design, refine, and maintain reusable UI components, patterns, and guidelines
- Define and evolve design tokens, including spacing, color, and typography
- Ensure platform consistency across Web, iOS, and Android
- Drive accessibility and inclusive design practices aligned to WCAG standards
- Work with engineers to ensure accurate component implementation and design-code parity
- Partner with product designers to support adoption, identify gaps, and ensure alignment
- Collaborate with brand and product design teams to align brand identity and system architecture
- Create and maintain documentation, usage guidelines, and examples
- Establish and improve contribution, versioning, and change-management processes
- Lead workshops, training sessions, and onboarding for the design system
- Audit product experiences to identify inconsistencies and propose system-driven solutions
- Reduce design and component fragmentation across surfaces
- Evaluate design system performance and future needs continuously
- Explore and experiment with AI tools for system creation, documentation, and scalability
- Identify opportunities where AI can accelerate component design, audits, token generation, and documentation
- Promote best practices for integrating AI into design and development workflow
What we're looking for
- 5+ years of experience in product design, UI/UX, or design-system-focused role
- Strong portfolio demonstrating systems thinking, component design, and visual craft
- Deep expertise in Figma, including variants, Auto Layout, tokens, and libraries
- Experience working closely with front-end engineers
- Strong understanding of accessibility, responsive design, and multi-platform workflows
- Excellent communication skills to explain system logic clearly
- Business-level English
Nice to have
- Familiarity with front-end technologies such as React component libraries, CSS architecture, and design token pipelines
- Experience building multi-brand or multi-platform design systems
- Interest in and practical experience leveraging AI tools to improve design efficiency and system scalability
- Business-level Japanese, written and verbal
- Japanese language level A2 preferred, optional
Good to know
- Employment status: full-time
- Work hours: full flextime, no core time
- Office location: Roppongi
- English language requirement: B2
- Recruiting cycle: application screening, skill assessment, interview, reference check, offer