Onyx
Onyx is a complete health and fitness tracker that runs entirely on your phone. Every entry — weight, meals, mood, photos, activity and cycle — is encrypted with AES-GCM and stored only on your device. No cloud servers, no account, no ads, no analytics, no tracking. Ever.
The only time Onyx touches the network is an optional, one-time download of its on-device AI model — and even then, nothing about you is ever uploaded. AI runs fully offline on your device.
What you can track
- Meals by breakfast, lunch, dinner & snack, with a built-in ~1,500-food dictionary that grows from your own entries
- Calorie-density “traffic-light” insight (green / yellow / orange) on every meal
- Water & fluid intake with one-tap logging
- Weight, with 7/30/90-day trend charts and full history
- Mood, with correlations against intake and activity
- Steps & active energy via Google Health Connect (Samsung Health and wearables)
On-device AI (offline at inference)
- Snap a photo of your plate for instant calorie estimates
- Scan a nutrition label, or simply describe your meal out loud
- A personal AI coach for your questions, plus tailored meal & workout plans
- Short daily insight notes across meals, activity and weight
Personalised targets
- Daily calorie targets from your profile (Mifflin-St Jeor BMR/TDEE)
- Goals for losing, gaining, building muscle or maintaining
- Optional target-weight pacing with safe limits
- Animated calorie-intake and activity rings
Private cycle tracking
- Opt-in menstrual tracking with phases, period and fertile-window predictions
- Flow and symptom logging, calendar view and reports
- So private that even the dates are encrypted — nothing ever leaves your phone
Stay motivated
- Streaks, badges and milestones for consistent logging
- Custom, fully-offline reminders
Yours to keep
- Encrypted backup export & import — move your data between devices with no cloud
- Guided walkthroughs to help you learn the app
Onyx is free to use. An optional one-time Onyx Pro purchase (no subscription) unlocks advanced analytics and extended features.
Your health data is yours alone.