Symbi - Your Biometric Tamagotchi

Meet your new digital companion! Symbi is a cute Halloween ghost that reflects your health and activity through its mood and appearance. The more you move, the happier your Symbi becomes!

Comment

Inspiration: I grew up with Tamagotchis and always loved the idea of a digital companion that responds to your care. I wanted to bring that nostalgic experience into the modern age by connecting it to something meaningful — your actual health data. The Halloween theme came naturally as a way to make health tracking feel fun rather than clinical.

What I Learned: Building Symbi taught me a lot about cross-platform health data integration (HealthKit and Google Fit have very different APIs!), state management with Zustand, and creating smooth 8-bit pixel animations in React Native without relying on game engines. I also deepened my understanding of privacy-first architecture — processing all health data locally was a core requirement.

How I Built It: The app is built with React Native and Expo for cross-platform support, TypeScript for type safety, and Zustand for state management. The ghost character is rendered as 8-bit pixel art using a custom canvas component, with emotional states calculated from health metrics. I used a phased development approach — starting with basic step tracking, then adding multi-metric analysis, and finally the evolution system.

Challenges: The biggest challenge was making health data feel personal without being intrusive. Balancing the "gamification" of health with genuine utility took several iterations. Getting the 8-bit animations to feel responsive and alive while maintaining 60fps performance was also tricky. Finally, ensuring the app works fully offline while still syncing data seamlessly required careful architecture decisions.

Built With

Share this project:

Updates