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Kynio - Fasting and Habits

KYNIO turns circadian fasting into an on-device RPG. Local-first SQLite privacy, solar dials, AI meal vision, and zero medical fluff.

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💡 Inspiration

Most health and fasting apps on the market today share the same three fatal flaws:

  1. Invasive Privacy Practices: They mandate cloud accounts, sell sensitive biometric habits, and force continuous tracking.
  2. Predatory Monetization & Dark Patterns: Confusing trial traps, bloated yearly plans, and artificial lock-outs.
  3. Generative "AI Slop": Unreliable, hallucinated health advice that overwhelms users with medical pseudo-science.

We built KYNIO around an uncompromising philosophy: Local-First, Zero AI Slop, and Circadian Harmony. Your body's metabolism evolved around the natural cycle of sunlight (melatonin surge, insulin sensitivity, and cellular autophagy). KYNIO translates that biological rhythm into a tactile, gamified mobile experience where 100% of your data stays on your device.

⚡ What It Does

KYNIO is a gamified circadian fasting and metabolic lifestyle tracker for Android and Web:

  • Circadian Solar Dial: A signature dome arc and dot-matrix clock that tracks your fast against the 5 metabolic phases (Digestion, Fat Burning, Ketosis, Autophagy, and Deep Renewal), complete with local solar calculation (Sunrise, Solar Noon, and Sunset) without GPS tracking.
  • 100% Local-First (SQLite + Drizzle ORM): Fasting intervals, water intake, body weight, and workout logs are stored exclusively in an on-device encrypted SQLite database. Zero account requirement.
  • Deterministic RPG Gamification: Earn XP, level up, maintain streaks, and complete weekly challenges generated deterministically from the ISO calendar. No pay-to-win mechanics or dopamine exploitation.
  • AI Meal Vision with Strict JSON: Snap a photo of your dish to estimate macros and calories via a secure Gemini Edge Function. Images are never stored, user identifiers are stripped, and output is strictly validated against TypeScript schemas before rendering.
  • Android Ecosystem Integration: Native Persistent Foreground Service (chronometer in notification bar), Home Screen AppWidget (fasting progress + 1-tap hydration), and Google Health Connect sync.

🛠️ How We Built It

KYNIO is built with an ultra-modern, production-hardened tech stack:

  • Frontend & Core: Expo SDK 57 (React Native 0.86, React 19, TypeScript strict mode) with expo-router typed routes.
  • Styling & Aesthetics: NativeWind v4 (Tailwind CSS) implementing the bespoke "Circadiano" design system (warm paper #EDE6D3, charcoal ink #3A3A38, and solar amber #D9922E).
  • Data Persistence: Expo SQLite coupled with Drizzle ORM for local transactional integrity, composite indexing, and soft-delete capabilities.
  • Monetization & In-App Purchases: Native billing via react-native-iap with server-side validation via Supabase Edge Functions (verify-purchase) ensuring tamper-proof Pro unlocks.
  • Optional Cloud Backup: Google OAuth with Supabase Row-Level Security (RLS) policies—activated only on voluntary opt-in.
  • Automated Quality: Full test pyramid with Jest (55 suites, 295 passing unit tests), contract tests for AI and legal sites, and end-to-end Maestro flows.

🧗 Challenges We Faced

  • Android 14+ Foreground Service Rigor: Google Play enforces strict foregroundServiceType="specialUse" policies. We engineered a native Kotlin module (FastingForegroundService) that updates the notification chronometer directly via Android SystemUI without draining battery or waking the JS thread.
  • Pure Local-First Analytics: Generating factual correlation insights (e.g. Early Time-Restricted Feeding adherence and hydration-to-completion rates) entirely on SQLite without relying on external cloud analytics or LLM tokens.
  • Rock-solid Version Synchronization: Coordinating synchronized version bumps across package.json, app.json, and native Gradle scripts to ensure reproducible AAB builds for the Google Play Store.

🏆 Accomplishments We're Proud Of

  • 100% GDPR Compliant from Day One: Zero medical liability, one-click full data export (JSON), and instant cryptographic erasure.
  • Google Play Production Release: Successfully verified and packaged for 18,800+ Android devices with high-level code obfuscation (R8/ProGuard) and optimal bundle size.
  • 295 Automated Tests: 100% test coverage across stores, metabolic calculators, and local encryption services.

🚀 What's Next for KYNIO

  • Expanding native Glance AppWidgets for more customization on the Android home screen.
  • Deep Wear OS companion tile for quick glance while on workouts.
  • Bringing the PWA web export to parity with native push notifications.

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