Cross-Platform
Healthcare Monitoring Platform
A unified healthcare monitoring platform spanning a custom smartwatch, React Native mobile app, and React.js web dashboard — all consuming a single Node.js backend with one auth contract. The smartwatch continuously monitors heart rate, SpO2, and GPS; the mobile app displays health metrics and manages sync; the web portal gives administrators real-time visibility across users.
Three product surfaces had evolved into three separate systems — tripling maintenance and fragmenting the user experience.
The healthcare monitoring product spanned three surfaces — a custom smartwatch collecting real-time health data (heart rate, SpO2, GPS), a React Native mobile app, and a web dashboard. Each had its own data fetching logic, auth flows, and interpretation of the health domain. A schema change to how health metrics were stored required three separate frontend updates. Bugs manifested differently per platform.
The mandate: ship all three surfaces from a single backend and a unified auth contract — without a full rewrite timeline.
One backend. One auth contract. Three production surfaces.
Architectural bets that turned three separate systems into one.
Every surface — web dashboard, mobile app, smartwatch sync layer — uses the same API client library with the same JWT header shape. Auth is handled once, at the client level, and attached to every request identically. This eliminated the three separate auth implementations that were causing divergent session behavior and made security auditing a single code path rather than three — which matters when the payload is personal health data.
Rather than maintaining separate iOS and Android codebases, React Native gave us one JavaScript codebase for the mobile layer. The custom smartwatch integrates via a BLE-based SDK bridge — the watch sends health data (heart rate, SpO2, GPS) to the mobile app, which aggregates and syncs to the backend. No separate backend integration on the watch; all data flows through the mobile layer, keeping the backend contract clean and consistent across all three surfaces.
The shared architecture only works if no one builds around it. I instituted a review checklist that every PR had to pass: no direct API calls outside the shared client, no inline auth logic, no platform-specific business logic. The 35% reduction in bug reports was a direct result of catching architectural violations at review time rather than post-ship.