Tether - MCAS Tracker
Know your triggers
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
New: 7-day free trial on Premium. Track MCAS flares, identify triggers, and generate doctor-ready reports — all on a private, calm health tracker.
Tether - MCAS Tracker is the mast cell activation syndrome (MCAS) tracker built for real life with this condition. Log flares, identify food and environmental triggers, track medications, and generate doctor-ready reports — all in a calm, private app designed for the daily reality of living with MCAS, POTS, EDS, and related chronic illness.
Your data stays on your device. No third-party analytics. No ads. No accounts.
WHAT YOU CAN DO FOR FREE
• Log flares with severity, body systems affected, and notes
• Track foods, environmental triggers, and medications
• Daily check-in and 30-day flare calendar
• Search and filter your full history
• Saved lists for medications, known triggers, and safe foods
• Daily reminders
• Emergency contact info
• Export all your data as JSON anytime
TETHER PREMIUM — separate in-app subscription required
Premium unlocks deeper insights:
• AI trigger correlation — surface what's most likely setting off your flares
• Pattern dashboard with frequency, time-of-day, and severity charts
• Doctor-ready PDF report you can share at appointments
• Food label scanner for spotting risky ingredients before you eat
• Weather and pollen tracking with daily environmental snapshots
• Comorbidity panel for POTS, EDS, Long COVID, and Fibromyalgia
• Apple Health sync for heart rate, HRV, sleep, and steps
All Premium features are clearly marked in the app and require a separate in-app subscription. You can use Tether's core logging features without subscribing.
SUBSCRIPTION PRICING
• Tether Premium Monthly — $5.99 per month
• Tether Premium Annual — $39.99 per year (save 44%)
• New subscribers get a 7-day free trial on the monthly plan
Payment is charged to your Apple ID at confirmation of purchase. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the current period (or before the free trial ends). Manage or cancel anytime in your App Store account settings.
BUILT FOR YOUR REALITY
Tether - MCAS Tracker is designed for people who live with chronic illness. The interface is calm, low-stimulus, and built to be usable on bad-pain or low-energy days. No streaks, no gamification, no judgment — just a tool that respects your time and energy.
PRIVACY-FIRST
Everything you log stays on your device. We don't run servers. We don't share your data with anyone. Apple Health data is read on-device only. Your location is only used to fetch local weather data and is never stored.
Privacy Policy: https://bagnew21.github.io/Tether/privacy.html
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
DISCLAIMER
Tether - MCAS Tracker is a personal health tracking tool. It is not a medical device and does not provide medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical concerns.
Ratings & Reviews
The developer, WILLIAM BARRY AGNEW, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- WILLIAM BARRY AGNEW
- Size
- 3.1 MB
- Category
- Medical
- Compatibility
Requires iOS 26.5 or later.
- iPhone
Requires iOS 26.5 or later. - iPad
Requires iPadOS 26.5 or later. - Mac
Requires macOS 26.5 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 26.5 or later.
- iPhone
- Languages
- English
- Age Rating
18+
- 18+
- Contains
User-Generated Content
Health or Wellness Topics
- In-App Purchases
Yes
- Tether Premium Annual $39.99
- Tether Premium Monthly $5.99
- Copyright
- © 2026 William Agnew