Stack - Caffeine & Sleep

Your Biohacking Dashboard

Free · In‑App Purchases · Designed for iPad. Not verified for macOS.

Precise. Personal. Science-backed. Stack is your personal biohacking dashboard — caffeine, sleep, water, supplements, and alcohol in one app. HOW IT WORKS Caffeine breaks down exponentially at an individual half-life. Stack calculates your current level from everything you've consumed: espresso, filter coffee, matcha, energy drinks, pre-workout. YOUR SLEEP WINDOW Instead of a fixed cutoff, Stack learns your personal threshold — the caffeine level below which you sleep well. Set your bedtime. Stack tells you if and when you'll be below it tonight. AUTO-CALIBRATION WITH APPLE HEALTH (PRO) Have an Apple Watch? Stack analyzes your heart rate variability (HRV) and resting heart rate relative to your caffeine level and calculates your true personal half-life. The more nights, the more precise the model. SLEEP INSIGHTS (PRO) How much deep sleep do you lose when caffeine is still in your blood at bedtime? Stack shows you the correlation from your own sleep data — not general studies, but your nights. WIDGET Caffeine level directly on your home screen — small, medium, or as a lock screen widget. YOUR DAILY STACK Stack tracks water, creatine, and supplements — and shows you when alcohol is additionally affecting your sleep. Everything in one place, without distraction. YOUR DATA STAYS YOURS No account. No cloud. All data stays on your iPhone. Apple Health is optional and used exclusively on-device. --- Stack Pro unlocks: Auto-Calibration · Sleep Insights · Health Dashboard · Notifications · Custom Presets · Tolerance Analysis Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

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AI recognition of drinks and apple watch app.

Version 1.4

The developer, Philipp Ritter, 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.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    • Philipp Ritter
    Size
    • 4.5 MB
    Category
    • Health & Fitness
    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.
    • Apple Watch
      Requires watchOS 26.5 or later.
    Languages
    • English and German
    Age Rating
    9+
    In-App Purchases
    Yes
    • Stack Pro – Yearly $14.99
    • Stack Pro – Monthly $2.99
    • Learn More
    Copyright
    • © Philipp Ritter
  • Privacy Policy

    • More by Philipp Ritter

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