Nodly: Sleep Debt & Caffeine

Circadian Rhythm & HRV Tracker

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

See your 14-day sleep debt, watch caffeine clear, and get tonight's personal cutoff time. Haptic breathing on Apple Watch. 100% on-device: no account, no servers. Sleep debt does not disappear in a single night. Nodly visualizes accumulated sleep debt, estimates daily cognitive readiness, tracks active caffeine clearance, and guides evening bedtime relaxation—all in one place. Powered exclusively by on-device processing from Apple Health data, Nodly helps you understand how much energy you have today, when to stop drinking coffee, and when to start winding down for sleep. [Key Features] 1. Sleep Debt & Daily Readiness - Estimates sleep debt in hours using a 14-day exponential decay weighted model. - Combines sleep duration, Heart Rate Variability (HRV), and resting heart rate against your 7-day baseline to display a 0–100 Readiness score. - Clearly flags "Preliminary" or "Not Measured" when data is insufficient. 2. Caffeine Clearance & Cutoff - 1-tap logging for coffee, tea, espresso, and energy drinks. - Calculates active blood caffeine (mg) using personal half-life exponential clearance. - Dynamically estimates your personalized evening caffeine cutoff time. - Syncs directly with Apple Health. 3. 24-Hour Circadian Timeline - Visualizes daily biological milestones: morning sunlight window, peak focus hours, caffeine cutoff, optimal bath timing, and recommended bedtime. - Weekly Bedtime Goals: set the bedtime and wake time you are aiming for on each weekday, and Nodly uses it as the basis for tonight's guide. 4. Apple Watch Haptic Sleep Guide - Silent, soothing wrist vibrations guide bedtime relaxation breathing without disturbing your partner. - 4-7-8 Sleep Breath (Inhale 4s, Hold 7s, Exhale 8s) - Box Breathing (Equal 4-4-4-4 rhythm) - 4-6 Calming Breath (Extended exhale) - View readiness, sleep debt, and log caffeine directly from your wrist. 5. Widgets & Live Activities - Lock Screen and Home Screen widgets for instant glanceability. - Interactive Home Screen widget with 1-tap caffeine logging. - Real-time caffeine tracking in Live Activities and Dynamic Island. [Zero-Knowledge Privacy] - No accounts, no sign-ins, zero external servers. - All biological calculations run 100% on your device. - Your daily morning check-in is saved to Apple Health so it stays with your Health data. - On-device CSV export for your sleep and caffeine records. [Nodly Pro Features] - Sleep Schedule Shift Plan: Stepwise circadian realignment over 3–14 days. - Today's Rhythm widget: today's circadian events and your next action on the Home Screen and Lock Screen. - 24-Hour Estimated Alertness Rhythm curve. - Caffeine sleep impact tendency analysis, with personal half-life auto-calibration. - Social Jetlag analysis & guidance. - Sleep Color Noises (Brown, Pink, Green, White, and Blue noise plus a 432Hz tone). [Terms & Privacy] - Terms of Use: https://eira-labs.com/terms.html#nodly - Privacy Policy: https://eira-labs.com/privacy.html#nodly [Medical Disclaimer] Nodly is a wellness tool designed for lifestyle and self-care tracking, not a medical device. All scores, sleep debt estimates, and recommendations are general guidelines and do not substitute professional medical advice, diagnosis, or treatment.

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The developer, Eiji Shibayama, 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

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

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    Information

    Seller
    Eiji Shibayama
    Size
    7.9 MB
    Category
    Health & Fitness
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    • Apple Watch
      Requires watchOS 10.0 or later.
    Languages
    English and Japanese
    Age Rating
    13+
    • 13+
    • Learn More
    • Infrequent
      Medical Treatment information

      Contains
      Health or Wellness Topics
    In-App Purchases
    Yes
    • 買い切り（Lifetime） $59.99
    • 年額プラン $22.99
    • 月額プラン $2.99
    • Learn More
    Copyright
    © 2026 Eira Labs
  • Developer Website
  • Privacy Policy

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