This Privacy Policy explains how KaterZerro ("we", "us", "our") processes personal data in connection with the KaterZerro iOS application ("App") and the website at katerzerro.com ("Website"). It applies to users in the European Economic Area (including Germany), the United States, and all other regions.
Key facts at a glance
- The App reads HealthKit data on your device and performs its regular analysis there. KaterZerro does not transmit HealthKit data to its own servers or use it for advertising.
- Optional Apple Intelligence features may process the already calculated information needed for a summary on your device or through Apple's Private Cloud Compute.
- We do not operate any backend infrastructure for the App.
- We do not sell, share, or use your data for advertising.
- We do not use cookies or tracking technologies on the Website.
Data controller
Dirk Lingstädt
KaterZerro
Gärtnerstraße 8
10245 Berlin
Germany
Email: info@katerzerro.com
Data processed by the App
Apple HealthKit data and app processing
The App requests access to Apple HealthKit to provide its core features. The following data types are accessed:
| Data type | Access | Purpose |
|---|---|---|
| Alcohol consumption (number of alcoholic beverages) | Read and write | Core tracking feature — recording and displaying your alcohol consumption |
| Heart rate variability (HRV SDNN) | Read-only | Biometric correlation — showing relationships between alcohol consumption and recovery metrics |
| Resting heart rate | Read-only | Biometric correlation — recovery trend analysis |
| Respiratory rate | Read-only | Biometric correlation — recovery trend analysis |
| Sleep analysis | Read-only | Biometric correlation — showing relationships between alcohol consumption and sleep metrics |
| Biological sex | Read-only | Guideline calculation — alcohol guidelines vary by biological sex |
KaterZerro does not transmit HealthKit data to its own servers. The App uses the HealthKit data you allow for its features and performs its regular analysis on your device. We do not use it for advertising or marketing purposes, sell it to data brokers, or share it with third parties for their own purposes.
You can revoke or adjust the App's HealthKit permissions at any time in iOS Settings → Privacy & Security → Health → KaterZerro.
Optional Apple Intelligence processing
For optional AI-powered summaries, the App prepares the relevant trend information on your device. Apple Intelligence then processes only the already calculated information needed for that task, either on the device or, when additional capacity is needed, through Apple's Private Cloud Compute (PCC). KaterZerro does not operate its own AI backend.
Apple states that Private Cloud Compute uses data only to fulfill the request and does not retain it after the response. You can turn off Apple Intelligence completely in iOS Settings at any time; the App's regular features remain available. For more information, see Apple's Apple Intelligence and Privacy information and the Private Cloud Compute Security Guide.
In-App Purchases
If you make a purchase within the App, the transaction is handled entirely by Apple Inc. through the App Store. We do not receive, process, or store your payment information. Please refer to Apple's Privacy Policy for details on how Apple handles transaction data.
No analytics, no crash reporting
The App does not include any analytics SDK, crash reporting service, or third-party tracking library. No usage data is collected from within the App.
Data processed by the Website
When you visit the Website, your web browser automatically transmits technical data to Cloudflare's infrastructure, including your IP address, browser type and version, pages visited, and the date and time of access. This data is processed solely to ensure the technical availability of the Website and to detect and prevent misuse. We do not use this data to identify individual users and we do not place cookies or tracking technologies. Log data is retained by Cloudflare in accordance with its applicable policies and legal obligations.
Legal basis for processing
HealthKit data — which includes health data as defined in Article 4(15) GDPR — constitutes a special category of personal data under Article 9 GDPR. We process this data on the legal basis of your explicit consent (Article 9(2)(a) GDPR in conjunction with Article 6(1)(a) GDPR). Consent is obtained in the App's privacy consent flow and through the iOS HealthKit permission dialog before the App accesses HealthKit. You may withdraw consent at any time by revoking the App's privacy consent and/or HealthKit permissions in iOS Settings, without affecting the lawfulness of processing carried out before withdrawal.
Website access logs are processed on the basis of our legitimate interest in maintaining a technically functioning and secure website (Article 6(1)(f) GDPR).
Data retention
HealthKit data written by the App (alcohol consumption entries) is stored by Apple's HealthKit framework on your device, subject to your iOS settings and Apple's data management policies. You can view, edit, and delete this data at any time through the Apple Health app. KaterZerro does not retain App data on its own external servers. Apple Intelligence processing through Private Cloud Compute is described in the section above.
Website access log data is retained by Cloudflare in accordance with its applicable policies and legal obligations.
Recipients and third parties
We do not share your personal data with any third parties for commercial purposes. The following technical parties are involved in operating the services:
- Apple Inc. — The App runs on Apple's iOS platform and uses Apple HealthKit, Apple Intelligence, Private Cloud Compute, and the App Store. Apple processes in-app purchase transactions, optional AI requests, and device/platform telemetry in accordance with Apple's Privacy Policy and the Apple Intelligence information linked above.
- Cloudflare, Inc. — Our Website uses Cloudflare's infrastructure, which processes technical access log data for delivery, security, and misuse prevention. See Cloudflare's Privacy Policy.
We do not share HealthKit data with third parties for their own purposes. Optional Apple Intelligence processing is limited to the already calculated information needed for the requested task, as described above. Website access logs are processed by Cloudflare as described above.
Your rights under GDPR (EEA users)
If you are located in the European Economic Area, you have the following rights under the GDPR. Because KaterZerro does not maintain a backend for App data, most App-related controls can be exercised directly through iOS Settings and the Apple Health app.
- Right of access (Art. 15 GDPR) — You can view all App-related health data at any time in the Apple Health app.
- Right to rectification (Art. 16 GDPR) — You can correct or edit health data entries directly in the App or in the Apple Health app.
- Right to erasure (Art. 17 GDPR) — You can delete individual alcohol entries in the App, or delete all App-related data in the Apple Health app. Uninstalling the App removes all App-specific settings from the device.
- Right to restriction of processing (Art. 18 GDPR) — You can restrict specific data types by adjusting HealthKit permissions in iOS Settings.
- Right to data portability (Art. 20 GDPR) — You can export your health data at any time through Apple Health app → Profile → Export All Health Data.
- Right to object (Art. 21 GDPR) — You can stop all processing by revoking HealthKit permissions at any time in iOS Settings.
- Right to withdraw consent (Art. 7(3) GDPR) — You can withdraw your HealthKit consent at any time in iOS Settings → Privacy & Security → Health → KaterZerro without any detriment.
To exercise any of these rights, or if you have questions that cannot be answered by the above, please contact us at info@katerzerro.com.
Supervisory authority
If you believe your data protection rights have been violated and you are located in Germany, you have the right to lodge a complaint with the competent data protection supervisory authority:
Berliner Beauftragte für Datenschutz und Informationsfreiheit
Friedrichstr. 219
10969 Berlin
www.datenschutz-berlin.de
If you are located in another EU member state, you may also contact the supervisory authority in your country of residence.
Your rights under CCPA (California residents)
If you are a California resident, the California Consumer Privacy Act (CCPA) provides you with specific rights regarding your personal information. We do not sell personal information. KaterZerro does not collect, store, or share App data on its own systems. Optional Apple Intelligence processing through Apple services is described above. You may exercise any CCPA rights by contacting us at info@katerzerro.com. We will respond to verifiable requests within the timeframes required by applicable law.
Children's privacy
The App is not directed at children under the age of 16. We do not knowingly collect personal information from children under 16. If you believe a child under 16 has used the App and you have concerns, please contact us at info@katerzerro.com.
Links to other resources
The Website and App may contain links to external websites or services that are not operated by us. We are not responsible for the privacy practices of those websites. We encourage you to review the privacy policy of any external site you visit.
Note on health information
The App and Website do not provide medical advice. All information and analysis in the App is for informational and self-monitoring purposes only and does not constitute medical advice, diagnosis, or treatment. The App is not a medical device. Always consult a qualified healthcare professional regarding any questions about your health or your alcohol consumption.
Changes to this policy
We may update this Privacy Policy from time to time. When we do, we will revise the "last updated" date at the bottom of this page. For significant changes, we will provide notice within the App. Your continued use of the App or Website after the effective date of a revised policy constitutes acceptance of the changes.
Contact
If you have any questions, concerns, or requests regarding this Privacy Policy or the processing of your personal data, please contact us: