Hypnogram

Privacy Policy

Last updated: July 20, 2026

Hypnogram is a sleep tracking app that helps you discover which of your habits are associated with your best and worst nights. This Privacy Policy explains what information the app uses, how it is handled, and the choices you have.

The short version: Hypnogram stores all of your sleep and habit data locally on your device. We do not operate servers that receive your health or habit data, we cannot see it, and we never sell it or use it for advertising.

Who we are

Hypnogram is operated by John Arthur Williams ("we," "us," or "our"). You can reach us at any time at support@hypnogramsleep.com or by mail at:

John Arthur Williams
311 Elm Street, Ste 270 PMB 1573
Cincinnati, OH 45202
United States

Data stored on your device

Hypnogram is designed to keep your information on your device. The following data is stored locally in an on-device database and is not transmitted to us:

Sleep data you choose to connect — such as sleep duration, sleep stages, timing, heart rate, and heart rate variability read from Apple Health, or sleep estimates generated by the app's optional microphone tracking.
Habits you log — such as alcohol, supplements, room temperature, sunlight, and any other variables or custom entries you record.
Your preferences — such as your target sleep schedule, reminder settings, and app settings.
Insights the app calculates — the correlations and patterns Hypnogram derives are computed on your device from the data above.

Because this data lives only on your device, deleting the app removes it. You can also delete all of your data at any time from within the app (You tab → Delete all data).

Apple Health data

If you choose to connect Apple Health, Hypnogram requests read-only access to sleep and related metrics (such as sleep analysis, heart rate, heart rate variability, resting heart rate, and blood oxygen where available). This access is used solely to calculate your sleep quality and surface habit correlations inside the app.

Health data accessed through Apple Health is used only to provide the app's features. It stays on your device, is never sold, and is never used for advertising or marketing. You can review or revoke Hypnogram's access at any time in Settings → Health → Data Access & Devices.

Microphone

Hypnogram offers an optional microphone-based sleep tracking mode for nights when you aren't wearing a wearable. If you enable it, the app listens for movement and sound during your sleep session to estimate sleep and wake times. This processing happens on your device. Audio is not recorded for playback, is not stored as audio files, and is not transmitted to us or any third party. You can decline microphone access or disable this mode at any time; the app functions without it.

Subscriptions and purchases

Hypnogram offers an optional premium subscription. Purchases are processed by Apple through the App Store, and subscription status is managed on our behalf by RevenueCat, Inc., a subscription management provider.

To manage your subscription and verify entitlements, limited information is processed by Apple and RevenueCat, which may include an anonymized app-specific user identifier, your subscription and purchase status, country or region, and device/platform information. We do not receive your name, email address, or payment card details through this process — Apple handles payment. RevenueCat processes this data as our service provider; you can review RevenueCat's privacy practices at revenuecat.com/privacy and Apple's at apple.com/legal/privacy.

Notifications

If you enable reminders, Hypnogram schedules local notifications on your device to prompt you to log your habits. These are generated on-device and do not require us to store or process your data on a server.

Information we do not collect

We do not operate analytics or tracking that profiles you.
We do not collect your name, email, contacts, photos, or precise location.
We do not sell or share your personal information.
We do not use your data for advertising, and we do not display third-party ads.

Children

Hypnogram is not directed to children under 13, and we do not knowingly collect personal information from children. The app is intended for adults tracking their own sleep.

Your choices and rights

Because your data is stored on your device, you are in control of it:

Access & export: Export your data at any time from the You tab.
Delete: Delete all of your data from the You tab, or remove it entirely by deleting the app.
Revoke permissions: Manage Health, microphone, and notification permissions in iOS Settings.

Depending on where you live, you may have additional rights over your personal information (such as under the GDPR or the CCPA). Since we do not hold your health or habit data on our servers, the most direct way to exercise these rights is through the on-device controls above. For any questions, contact us at support@hypnogramsleep.com.

Not medical advice

Hypnogram is not a medical device. It surfaces statistical associations in your own data and does not provide medical diagnosis, treatment, or advice. Always consult a qualified healthcare professional (such as a doctor) for decisions about your health, sleep, or any medical condition.

Changes to this policy

We may update this Privacy Policy from time to time. When we do, we will revise the "Last updated" date above. If we make material changes, we will provide notice through the app or on this page. Note: our operating entity may change to a limited liability company in the future; if so, this policy will be updated to reflect the new entity name, and your data practices will remain as described here.