Privacy Policy

for the Android app Kellerkompass and the website kellerkompass.at. Effective 22 October 2026. Deutsche Fassung (the German version prevails in case of doubt)

In short: Kellerkompass has no internet permission. Everything you enter or photograph in the app stays on your device; I, the developer, receive none of it. There is no account, no advertising, no analytics or crash reporting, and no data is sold or shared. The website sets no cookies and uses no tracking.

1. Controller and contact

This policy applies to the app Kellerkompass (Google Play, package name at.kellerkompass) and the website kellerkompass.at. Developer and data controller:

Please use the subject “Privacy”. I reply within one month.

2. Data the app processes

The app only processes what you enter, photograph or select yourself, and only to provide the feature you are using. All of it is stored and processed exclusively on your device.

• Details of your wines: name, winery, vintage, grape variety, wine type, price, drinking window, ratings, tasting notes, favourites and shopping list. Purpose: managing your collection.
• Storage locations, racks and stock: the layout of your racks, where each bottle is stored, and bottles added or removed. Purpose: finding, storing, moving and checking bottles.
• Photos: photos of bottles and labels you take with the app. They are kept in the app’s private storage. The app also saves a copy to your gallery in the folder “Pictures/Kellerkompass” (see section 6).
• Camera image: while you take a photo or use the augmented reality (AR) rack view, the live camera image is analysed on the device, for example to cut out a label or to locate the rack. Only photos you explicitly take are stored, plus, for the AR view, a map of each calibrated rack: feature points and a few reference images of the rack front so the app can recognise it again. Both are kept in the app’s private storage.
• Files you select: an Excel spreadsheet or backup file you import. The app only reads the file you pick in Android’s file picker.
• Settings and purchase status: for example whether you have already been asked about notifications and whether Kellerkompass Pro is unlocked.

The app does not collect your name, email address, location, contacts, advertising ID, App Set ID, device identifiers such as IMEI or serial number, usage statistics or crash reports.

3. Permissions

• Camera: for taking photos and for the AR view. Android asks you before the app uses the camera for the first time.
• Notifications: for a reminder when a wine is ready to drink. The check runs once a day on the device. Android asks you first; you can turn it off at any time in Android settings under Apps, Kellerkompass, Notifications.
• Storage (Android 9 and older only): to save the photo copy to the gallery.

Kellerkompass has no internet permission, so the app itself cannot send any data over the network.

4. Sharing with third parties

I do not sell or share any data. I receive no data from the app. The following services and components are involved:

• Google Play Services for AR (ARCore): This application runs on Google Play Services for AR (ARCore), which is provided by Google and governed by the Google Privacy Policy. ARCore is a separate Google app that you install from the Play Store. How Google handles data is described in “How Google Play Services for AR handles your data”. Kellerkompass does not use Cloud Anchors or the Geospatial API; the calibration of your racks stays on the device.
• Libraries running on the device: Google ML Kit, ONNX Runtime, LiteRT and OpenCV analyse photos and camera images on the device only. According to Google, ML Kit may send performance and usage metrics to Google; because Kellerkompass has no internet permission, this is not possible from within the app.
• Google Play: installation, updates and purchases go through Google Play, where Google processes data under its own privacy policy.
• What you share yourself: backup files and spreadsheets you save or share end up wherever you send them, for example a cloud storage service or an email. From there, that service’s terms apply.
• Legal obligations: data I receive from you (for example by email) is only disclosed if I am legally required to do so.

5. Kellerkompass Pro (in-app purchase)

If you buy Kellerkompass Pro, the purchase is handled by Google Play. You only give payment details such as card numbers to Google; I never receive them. The app only receives confirmation from the Play Store on your device that the purchase is valid, and stores locally that Pro is unlocked. For my accounting, Google provides me with order data such as order number, date, product, price and country. I keep this for as long as tax law requires (seven years in Austria, § 132 BAO). Legal bases: performance of a contract and legal obligation (Art. 6(1)(b) and (c) GDPR).

6. Security

• The app’s database is encrypted with SQLCipher (AES-256). The key is protected by your device’s Android Keystore.
• All app data is kept in the app’s private storage, which other apps cannot access.
• Android’s automatic cloud backup is disabled for Kellerkompass, so app data is not copied to the cloud without your knowledge.
• The website is served encrypted over HTTPS.

Please note: backup files (ZIP) and Excel spreadsheets you export are not encrypted. The photo copies in the gallery (Pictures/Kellerkompass) are visible to other apps with access to your photos; if a photo backup such as Google Photos is active, it may upload these images to the cloud.

7. Retention and deletion

• Data in the app is kept until you delete it. You delete individual wines, bottles, racks and notes directly in the app.
• Everything at once: uninstalling the app or clearing its storage in Android settings deletes all app data, including the automatic database copies the app makes before updates (at most four are kept).
• Photos in the gallery (Pictures/Kellerkompass) remain after uninstalling. You delete them in your gallery.
• Backup files and spreadsheets are deleted wherever you saved them.
• Emails to me are deleted once your request is resolved, at the latest after twelve months, unless I am legally required to keep them longer.
• Purchase data (section 5) is kept for seven years.

Kellerkompass has no user accounts, so there is no account to delete.

8. Third-party data in the app

The app contains a list of European wineries as an input aid. This data comes from OpenStreetMap (© OpenStreetMap contributors, ODbL licence), is included in the app and is not downloaded.

9. The website kellerkompass.at

The website is hosted by World4You Internet Services GmbH in Linz, Austria. When you visit it, the server stores technically necessary access data (IP address, time, page requested, browser identifier) in log files so the website can be operated securely. How long these logs are kept is determined by World4You. The legal basis is my legitimate interest in secure operation (Art. 6(1)(f) GDPR).

The website sets no cookies, uses no analytics or advertising services and loads no content from other servers; the fonts are hosted on this server too.

If you email me, for example via the feedback page or “Feedback senden” (send feedback) in the app, I only use your details to reply and to improve the app (Art. 6(1)(b) or (f) GDPR). “Send feedback” opens your email app and adds the app version, phone model and Android version to the draft; you see everything before sending and can change or delete it. Nothing is sent until you tap send yourself.

10. Children

Kellerkompass is intended for adults because the app relates to alcohol. It is not directed at children and does not knowingly collect data from children.

11. Your rights

Under the GDPR you have the right of access, rectification, erasure, restriction of processing, data portability and objection. Contact me at the email address in section 1. Data that exists only on your device cannot be seen or deleted by me; you alone control it (see section 7).

You may also lodge a complaint with the Austrian Data Protection Authority: Barichgasse 40–42, 1030 Vienna, Austria, dsb.gv.at.

12. Changes

If the way Kellerkompass or the website handles data changes, I will update this policy and the date above. The current version is always available at kellerkompass.at/privacy.html.