Two platforms, two bug lists, one missing shared layer

Read as two platform problems it is two backlogs and two engineers. Read as one product implemented twice it is drift — and drift keeps producing defects no matter how many you close.

The same clinical feature existed in Kotlin and in Swift, maintained separately and diverging quietly. A fix on one side was half a fix, and nothing in the process noticed.

This was 2021, with no coding assistant: the cross-platform architecture, the migration plan and the encryption library were designed and written by hand.

• The Personal Health Manager app migrated onto one React Native codebase, resolving 20+ native defects and unifying both platforms.
• The mobile UI architecture and API integration for the core clinical features — DNA reports and the survey instruments — plus web-to-mobile account linking, multi-account support, infinite scroll over large datasets, and charting.
• The client-side encryption library protecting patient data at rest, written after a vulnerability assessment and penetration test.
• A design-revamp refactor that cut code complexity roughly in half and improved responsiveness by about a third.

native defects resolved

20+native defects resolved

of penetration-test findings closed

60%of penetration-test findings closed

fewer post-launch bug reports

~30%fewer post-launch bug reports

to release both patient and physician apps

6 monthsto release both patient and physician apps

Delivered remotely from Indonesia to a Singapore team, coordinating an outsourced group and running the knowledge transfer.

• React Native
• TypeScript
• Redux
• Redux Saga
• Kotlin
• Swift