Effective date: 9 April 2026
Your shift schedules and sleep preferences are stored on your device only and never leave your phone. We use minimal, privacy-respecting analytics (TelemetryDeck) to understand how the app is used and Apple's MetricKit for crash diagnostics. No personally identifiable information is collected through either service. We do not sell or share your data with third parties.
Zeitgeber is an iOS application developed and published by Helvellyn Ventures Ltd, a company registered in England and Wales. We are registered with the Information Commissioner's Office (ICO) as a data controller.
When this policy says "we", "us", or "our", it means Helvellyn Ventures Ltd. When it says "you" or "your", it means you, the person using the Zeitgeber app.
Zeitgeber stores the following information on your device (using iOS UserDefaults and Keychain storage). This personal data is not transmitted to us or any third party:
All of this information is entered manually by you. Zeitgeber does not integrate with Apple HealthKit or any other health platform.
Zeitgeber uses two minimal, privacy-respecting services to help us improve the app:
We use TelemetryDeck to collect anonymised, aggregate usage analytics. This helps us understand which features are used and where users encounter issues. TelemetryDeck does not collect personally identifiable information, does not use advertising identifiers, and does not track users across apps. Data is processed on EU servers (Frankfurt). For more detail, see TelemetryDeck's privacy policy.
Examples of what we track: which onboarding steps are completed, which shift patterns are chosen, and whether the paywall is viewed. We never track the content of your shifts, sleep times, or any health-related information.
We use Apple's MetricKit framework to collect anonymised crash reports and performance diagnostics. This data is processed by Apple and helps us identify and fix issues. No personally identifiable information is collected through this process. Aggregated diagnostic data is accessible to us through Xcode Organizer, but it contains no information that could identify individual users.
To be explicit about what Zeitgeber does not do:
The information you enter is used solely to generate personalised sleep and circadian rhythm recommendations within the app:
Your personal data (shifts, sleep preferences, chronotype) is processed entirely on your device. The only data that leaves your device is the anonymised analytics and diagnostics described in Section 3 above.
Under UK GDPR, we process your data on the basis of legitimate interests. For on-device data, this means providing the core functionality of the app that you have chosen to use. For anonymised analytics and crash diagnostics, our legitimate interest is improving app quality and stability. This processing is minimal and proportionate: no personally identifiable information is collected, and TelemetryDeck does not use advertising identifiers or cross-app tracking.
For subscription management, Apple acts as the merchant of record. Apple's privacy policy governs how Apple handles your payment information. We receive only a non-identifiable record of subscription status.
We do not sell or share your personal data with any third parties. There are no advertising partners or data brokers involved.
The third-party services involved in Zeitgeber are:
Your data is retained on your device for as long as you have the app installed. You can delete all data at any time by:
The trial install date stored in Keychain may persist after app deletion in some iOS configurations. This contains no personally identifiable information; it is only a date. Anonymised analytics data held by TelemetryDeck and crash diagnostics held by Apple cannot be linked back to you and are subject to those services' own retention policies.
You have the following rights regarding your personal data. Because all data is stored on-device, most of these rights are exercisable directly through the app itself:
| Right | How to exercise it |
|---|---|
| Right of Access | View all entered information within the app at any time |
| Right to Rectification | Edit or update any information directly within the app |
| Right to Erasure | Use the reset function in Settings, or delete the app |
| Right to Portability | Your data exists on your own device - you have full control |
| Right to Object | Contact us at support@zeitgeber.app with any concerns |
| Right to Complain | Lodge a complaint with the ICO at ico.org.uk |
To exercise any of these rights or to raise a concern, please contact us at support@zeitgeber.app.
Zeitgeber is designed for adults in the workforce and is not directed at children under the age of 16. We do not knowingly collect information from anyone under 16. If you believe a child under 16 has provided information through the app, please contact us so we can assist.
In line with Apple's requirements, Zeitgeber's App Store privacy nutrition label reflects the data practices described in this policy. Anonymised usage data is collected for analytics purposes but is not linked to your identity and is not used for tracking. A Privacy Manifest file (PrivacyInfo.xcprivacy) is included in the app and declares our use of UserDefaults and MetricKit.
If we make material changes to this Privacy Policy (for example, if we introduce cloud sync or HealthKit integration) we will notify you via an in-app notice before any such changes take effect. The updated policy will be published at zeitgeber.app/privacy with a new effective date.
We encourage you to review this policy periodically. Continued use of the app after changes take effect constitutes acceptance of the updated policy.
If you have any questions about this Privacy Policy or how we handle your data, please get in touch:
We aim to respond to all privacy enquiries within 5 working days.