Privacy Policy

Last updated 30 August 2026

What this policy covers

This policy explains how Diel handles information when you use the Diel iPhone and Apple Watch apps. Diel is published by the Diel team (“Diel”, “we”, or “us”).

Health data

With your permission, Diel reads selected data from Apple Health, including heart-rate variability, heart rate, sleep, respiratory rate, wrist temperature, activity, daylight exposure, State of Mind, and related signals. If you choose the hormonal-cycle profile, Diel may also read cycle information you have logged in Apple Health.

Diel uses this information on your device to calculate a relative index against your personal baseline and to produce insights. Diel does not write data back to Apple Health.

Information you enter

You may enter context such as caffeine, alcohol, mood, perceived stress, meals, work intensity, and other notes. This information is stored locally with your Diel data and is used to personalize your index and insights.

Analytics and purchases

Diel uses privacy-conscious analytics services to understand anonymous app usage, diagnose problems, and improve the product. Analytics events are not accompanied by your HealthKit readings. Purchases and subscriptions are processed by Apple and our payment provider; we do not receive your full payment details.

Sharing and deletion

Diel does not require an account. You control access through Apple Health permissions and can revoke it at any time. You can delete Diel’s locally stored data from the app’s data settings or by deleting the app. If you contact support, we receive the details you choose to include in your message.

Children

Diel is not directed to children under 13, and we do not knowingly collect personal information from children.

Changes

We may update this policy as Diel changes. The date above shows when it was last revised. Material changes will be communicated in the app where practical.

Contact

For privacy questions, please use our support page.