Supercharging User Engagement: How Mercari is Using Server-Driven UI to Reduce Time-to-Market

Mercari's Growth Platform team implemented Server-Driven UI (SDUI) architecture through a feature called EGP Card to accelerate campaign deployment and reduce time-to-market. The solution allows UI configuration to be controlled remotely via JSON schemas rendered natively on iOS, Android, Web, and Flutter, eliminating the need for app releases when updating campaign designs. Key implementation challenges included versioning and backwards compatibility, cross-platform rendering consistency, personalization through placeholder replacement, and state management for interactive components. The team addressed these through graceful degradation, comprehensive testing automation, AI-assisted code generation, and custom component patterns. While requiring significant upfront investment, the SDUI approach dramatically reduced campaign iteration time from weeks to minutes and enabled rapid A/B testing.