Supercharging User Engagement: How Mercari is Using Server-Driven UI to Reduce Time-to-Market
Article Summary
Stefan from Mercari's Growth Platform team reveals how they eliminated app releases for marketing campaigns. Their server-driven UI solution turned weeks of development into minutes of drag-and-drop configuration.
Mercari's Growth Platform team was stuck in a painful cycle: every marketing campaign required custom native code, QA testing across platforms, and waiting for app store releases. They built EGP Card, a server-driven UI system that lets marketers design and deploy campaigns instantly without touching client code.
Key Takeaways
- Campaign updates now deploy instantly vs waiting for app store releases
- Native renderers built for Android, iOS, Web, and Flutter with shared test cases
- Versioned schemas with graceful degradation prevent crashes on older app versions
- AI agents helped build Flutter renderer and generate components from Figma designs
- Personalization uses backend placeholder replacement for dynamic user-specific content
Mercari transformed marketing velocity by moving UI configuration from native code to server-controlled JSON schemas, enabling instant campaign updates without app releases.
About This Article
Mercari's Growth Platform team had rendering inconsistencies across Android, iOS, Web, and Flutter. When they built native SDUI renderers, each platform interpreted styling properties and components differently, which meant users saw different experiences depending on what device they used.
Stefan's team added unit and screenshot testing before pushing to production. They integrated screenshot testing into their CI/CD workflows and built tooling to compare rendering across all platforms side by side. This made it fast to spot and fix differences.
The team got consistent rendering across platforms by sharing JSON test cases between them and using AI agents to generate code across languages. This let them build the Flutter renderer as a native Dart plugin instead of dealing with complex Android and iOS channels.
