Privacy at Coffee Rings

Privacy Policy (App "Coffee Rings")

Last updated: July 2026

Controller and contact

Michael K. Knop
Kerbelweg 5b
22337 Hamburg
Germany
Email: support@coffeerings.de

Basic principle of the app

Coffee Rings does not require a user account and generally does not ask for master data such as your name or address. Recipes, shot data, ratings, notes and images entered by you are generally stored locally on your device. Free-text fields and images may, however, contain personal information if you enter or add such information yourself.

The developer has no automatic access to locally stored content. Data may nevertheless reach other parties when you use system backups, cloud functions, exports, support contact or optional AI processing.

Local storage and deletion

The app stores in particular espresso recipes, shot parameters, shot history, ratings, notes, images, drafts, continuations and app settings in the local app storage of the respective device. You can delete content within the app or reset settings. Uninstalling the app may remove local app data from the device.

Backups, iCloud or CloudKit data, Android backups, exported files or support emails already sent may continue to exist independently. Coffee Rings cannot fully control storage location, sharing and deletion outside the app.

Storage & synchronization on Apple devices

All core features of the app work offline and without an account. If you enable iCloud for Coffee Rings in iOS (Settings → Apple ID → iCloud → Apps using iCloud → Coffee Rings), iOS/iPadOS will additionally sync your recipes into your private iCloud database (powered by Apple’s CloudKit service). Only you and your Apple ID can access this space; the developer has no general access to your iCloud account.

Apple provides the platform and cloud infrastructure for this. You can influence, disable or manage stored data through your Apple or iCloud settings. Apple’s privacy terms and account settings also apply to processing by Apple.

Backup on Android devices

The Android version stores recipes, shot history and session data in a local Room database inside private app storage. Recipes, drafts, continuations, images and app settings are also stored as local app files. The OpenAI API key is stored separately in encrypted Android SharedPreferences.

The Android project sets android:allowBackup="true". No custom dataExtractionRules or fullBackupContent rules are configured. On supported Android devices, the operating system may therefore back up app data as part of Android’s backup functionality and restore it after reinstalling the app or moving to another device. Whether and how this happens can depend on device settings, Google account, Android version and manufacturer configuration.

Backup is controlled by Android or by the backup service used by the device. The developer has no direct access to these backups. Deletion and retention within the platform or Google account are also governed by the settings and privacy terms of the respective provider.

Coffee Rings also provides manual import and export functions for recipe archives and settings. Cross-platform transfer is possible through these export files, including Android to iOS and back, Android to Android, and iOS to iOS.

Use of AI features (OpenAI)

The iOS and Android versions optionally allow you to enter your own OpenAI API key to receive AI-based recommendations. The AI feature is voluntary; Coffee Rings remains usable without AI.

Only when you actively use the AI feature are the shot and rating data intended for analysis transmitted directly between your device and OpenAI and authenticated with your personal API key. This may include brewing parameters, taste ratings and notes. Do not enter personal information in notes or other fields if those fields may become part of an AI request.

Your API key stays in the protected app storage of the respective platform and is only used when your device talks directly to OpenAI. On Android, the key is stored in encrypted SharedPreferences; on Apple devices, it is stored in protected app storage and, if enabled, in your private iCloud backup. The developer has no central access to the API key, transmitted input or AI output.

OpenAI processes data under the terms applicable to your OpenAI account and API use. Possible costs arise directly with OpenAI. OpenAI’s privacy and API terms as well as the settings of your OpenAI account apply.

Export functions

Coffee Rings offers export and import functions for recipe archives, settings and individual content. You decide whether and where to save exported files or with whom to share them. Exported files can be stored outside the app; after export, storage location, sharing and deletion are no longer fully controlled by Coffee Rings.

Support by email

If you contact us by email, your sender address, message content and voluntarily submitted diagnostic data, screenshots or attachments are processed to handle your request.

For contract-related or app-use-related requests, processing is based on Art. 6(1)(b) GDPR. General requests are processed on the basis of Art. 6(1)(f) GDPR; the legitimate interest is handling the request properly. The data is deleted once the request is completed and no statutory retention obligations prevent deletion.

External processing only through enabled or system-level features

The developer does not sell app data, does not use app data for advertising or profiling and does not operate own app tracking. Data may, however, be processed by external providers when optional features or system-level services are enabled, in particular Apple, Google, OpenAI, email providers and actually used payment or support providers.

Where processing outside the EU or EEA may occur, the privacy information and safeguards of the respective provider apply.

Voluntary support

On Apple devices, voluntary tips (“Tip Jar”) are processed by Apple Inc. through your App Store account. Payment data is generally processed by Apple. The developer does not automatically receive complete payment data for these purchases, such as name, address or payment information.

In the Android version, voluntary support can be provided through an external Buy Me a Coffee link. If you actively open that link, you leave Coffee Rings; the privacy terms of the external provider then apply.

Legal bases

Where personal data is processed in connection with user-initiated features or support, processing is based, depending on the context, on Art. 6(1)(b) GDPR or Art. 6(1)(f) GDPR. The legitimate interest includes secure technical provision, abuse prevention and handling general requests. Optional services are used only through your activation or through your system or account settings.

Your rights

Data subject rights against the developer apply where the developer actually processes personal data, in particular in support communication. Subject to the statutory requirements, you have rights of access, rectification, erasure, restriction of processing, data portability and objection.

You manage locally stored app data yourself within the app or through your device. For iCloud, Android backups, OpenAI and payment providers, their own procedures and responsibilities also apply. Privacy requests can be sent to support@coffeerings.de.

Right to lodge a complaint

You have the right to lodge a complaint with a data protection supervisory authority. For Hamburg, the Hamburg Commissioner for Data Protection and Freedom of Information is the relevant authority.

Changes to this policy

This privacy policy may be updated if necessary. The current version will be available within the app, on this website and in the store information.