Just Eat Takeaway's design system, PIE (Principles for Interfaces and Experiences), powers a global product ecosystem spanning customer apps, partner tools, courier platforms, and internal systems. Serving over 78 designers and 500+ engineers, PIE supports Web Components, React, React Native, iOS, and Android. Built through collaboration between design, brand, and engineering, PIE drives alignment across platforms, ensuring accessible, consistent, and scalable experiences. Guided by its principles—empowered, consistent, inclusive, and effective—PIE is both a functional framework and a creative foundation. Its evolution enables Just Eat Takeaway to deliver cohesive products across 17 countries while adapting to innovation and growth.

PIE's adoption strategy is built on a clear vision: making products better and teams more efficient. A dedicated, multidisciplinary team drives this effort through education, clear documentation, and feedback loops that connect design and engineering. Growth through mergers introduced multiple design languages and legacy systems, but PIE addressed this challenge by consolidating platforms, unifying UI patterns, and embedding a single design language across regions.

Adoption is reinforced through creativity and craft—building excitement and trust by delivering inspiring, high-quality components. Native demo apps for iOS and Android, powered by design tokens, have bridged the gap between design and engineering, ensuring accuracy and consistency.

Ongoing advocacy through mentoring, guild involvement, and onboarding new joiners keeps engagement strong. A flexible structure of core and local pillar systems balances consistency with adaptability, allowing teams to extend PIE to meet their specific needs. By solving real pain points—from accessibility to theming—PIE positions itself not just as a toolkit but as the foundation for scalable, user-focused product development.

PIE has transformed Just Eat Takeaway's digital landscape into a unified, efficient ecosystem. Adoption spans 100% of iOS and Android products and 80% of web platforms, with every designer and developer drawing from the same source of truth. This consistency enhances accessibility, speeds delivery, and ensures brand alignment at scale. A custom usage tracker provides visibility into adoption, informing priorities and highlighting progress. Beyond technical gains, PIE fosters collaboration by creating a shared language between design and engineering. The result is faster innovation, stronger cohesion, and a culture where teams trust the system to deliver better products together.