Creating Fleet's New Design System

01 — Context

Since Fleet was created, developers had continuously built a fully custom Storybook component library without a shared foundation or systemic logic. This accumulated 3 years of design debt: duplicated components, inconsistent styles, no documentation. Every new feature took 30% longer due to the lack of consistency. Fleet's rebranding became the opportunity to both modernize the interface for a more B2B-oriented audience and lay the foundations for a coherent, modular and scalable Design System.

Interface avant la mise en place du Design System

My role: co-lead the design system, building it on Material UI and Atomic Design principles, with measurable adoption.

02 — Discovery

We began with a full audit of Fleet's 2 products, interviewing 6 developers and 2 designers, to identify UI misalignments, component variations and interaction problems across pages. The analysis revealed duplication, lack of uniformity and the absence of shared standards: 340 components in the codebase for only 80 distinct patterns needed. To structure the redesign, we adopted Material UI as a React-based open-source foundation, accelerating development, ensuring built-in consistency and reducing technical complexity. We then defined an atomic structure, organizing components into atoms, molecules and organisms to enable reuse, scalability and easier maintenance.

03 — Delivery

We built a robust, actionable Design System for both design and development teams: harmonized colors and typography with the new branding, reduced border radius for a more structured B2B look, a consistent icon set and updated illustrations aligned with the brand identity. 80 documented components were delivered with a Figma library connected to code via Storybook and a documentation site on Zeroheight. Each component includes clear usage guidelines to ensure consistency and ease of adoption. Results after 6 months: −40% feature development time, onboarding reduced to 3 days.

04 — Learnings

A design system is not a design project: it's a product whose users are the teams. Adopting this mindset from the start (interviews, roadmap, feedback loops) was the key to adoption. Timing also mattered: pairing the DS with a rebranding created the rare conditions where both design and engineering were aligned on the need for change, making it easier to justify the investment and accelerate adoption.