Privacy Policy

Effective date: October 14, 2026 · Applies to the iOS app “Coin Value” (German: “Münzen Wert”) and this website.

The short version: your collection stays on your iPhone. When you identify a coin, the photos are sent to our server in the EU, passed to an AI model, and discarded once the answer is back. Purchases go through Apple and RevenueCat. Usage statistics (Google Analytics for Firebase) are pseudonymous, never used for advertising and can be switched off in the app. No accounts, no ads, no tracking across apps.

1. Controller

Caspar Baumeister
Dernburgstraße 7
14057 Berlin, Germany
caspar.baumeister.dev@gmail.com

As a sole developer I am not required to appoint a data protection officer. For any question about this policy or your data, please e-mail me.

2. What the app processes, and why

2.1 Coin photos (AI identification)

To identify a coin, the app sends the photos you take (front, back, optional detail, scaled down to a maximum of 1600 px), your app language (“de”/“en”) and a random installation ID to our server. The server is a Google Cloud Function (Firebase) running in the region europe-west1 (Belgium). It forwards the images to the Google Gemini API, which returns the identification and value estimate. The photos are held in memory only for the duration of the request and are not stored on our server or in the AI service after the response has been delivered; we keep neither the images nor the result. Technical request logs (timestamp, request ID, status, installation ID, IP address, never the images) are retained for up to 30 days to detect abuse and errors.

Please photograph coins only. Do not include documents, faces or other personal information in the frame.

Legal basis: Art. 6(1)(b) GDPR (performance of the contract: identification is the core service of the app). The installation ID and rate limiting serve our legitimate interest in protecting the service from abuse (Art. 6(1)(f) GDPR).

2.2 Metal prices

The value estimate includes the metal value of silver and gold coins. Spot prices are fetched by our server, not by your device, so no data about you is sent to a price provider.

2.3 Purchases (Coin Value Plus)

Subscriptions are processed by Apple through the App Store. To check whether Plus is active and to restore purchases, the app uses RevenueCat (RevenueCat, Inc., USA). RevenueCat receives a random app user ID generated on your device, the App Store receipt / transaction information (product, dates, status) and basic device information. We never receive your name, Apple ID, address or payment details.

Legal basis: Art. 6(1)(b) GDPR (performance of the contract). Transfer to the USA is covered by the EU-US Data Privacy Framework and/or EU standard contractual clauses in RevenueCat's data processing agreement.

2.4 Usage statistics (Google Analytics for Firebase)

The app records simple usage events, for example “onboarding step 3 viewed”, “paywall viewed”, “scan completed (confidence: high)” or “coin added”, together with technical information (app version, iOS version, device model, language, and the country and region derived from the IP address). We use Google Analytics for Firebase (Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland) for this. Events are tied to a random app instance ID that the Firebase SDK creates on your device, not to your name, e-mail or Apple ID. We do not use the advertising identifier (IDFA) or the vendor identifier (IDFV), we do not set a user ID, advertising features (ad storage, ad personalisation, Google signals) are switched off, and we do not track you across other companies’ apps or websites. Google Analytics does not store IP addresses; it only derives the country and region from them. Photos, coin names, values, notes and search terms are never part of these events. Google may process the data in the USA; the transfer is covered by the EU-US Data Privacy Framework (Google LLC is certified) and Google’s data processing terms. Event-level data is deleted after at most 14 months.

You can switch the usage statistics off at any time in the app under Settings › Share anonymous usage data; the app then sends no more usage events.

Legal basis: Art. 6(1)(f) GDPR, our legitimate interest in understanding where the app is confusing and in fixing errors, implemented with privacy-friendly settings (no advertising identifiers, no user ID, no advertising features, opt-out at any time).

2.5 Data stored on your device only

Your collection (coin photos, identification results, quantities, notes), the value history of your collection, your settings and the installation ID are stored locally on your iPhone. They are never uploaded to us. You can delete all of it at any time via Settings › Delete all data in the app, or by deleting the app. Depending on your iCloud settings, iOS may include app data in your device backup; that is controlled by Apple and you.

2.6 Camera and photo library

The app asks for camera access to photograph coins, and, only if you choose a picture from your library, for access to the selected photos. Both permissions are optional and can be revoked in iOS Settings. The app never scans your photo library on its own.

2.7 Links to Apple, support e-mail

“Manage subscription”, “Rate the app” and “Report a problem” open Apple's pages or apps; Apple's privacy policy applies there. If you e-mail us, we process your e-mail address and the content of your message to answer you (Art. 6(1)(b) and (f) GDPR) and delete the correspondence once the matter is closed, unless statutory retention periods apply.

3. This website

This site is hosted on Firebase Hosting (Google Ireland Limited / Google LLC), delivered via a global content delivery network. When you open a page, the server processes your IP address, the requested URL, the time, browser and referrer in technical logs to deliver the page and ensure security (Art. 6(1)(f) GDPR). The site uses no cookies, no analytics and no external fonts or scripts. Your language choice (EN/DE) is stored in your browser's local storage only.

4. Recipients and international transfers

We do not sell personal data and do not share it with anyone else.

5. Retention

• Coin photos: not stored, discarded immediately after the identification response.
• Server request logs (without images): up to 30 days.
• Usage events: up to 12 months, then deleted or aggregated.
• Purchase records at RevenueCat: for as long as your subscription exists, plus statutory retention periods.
• Data on your device: until you delete it in the app or delete the app.

6. Your rights

Under the GDPR you have the right to access the personal data we hold about you, to rectification, erasure, restriction of processing, data portability, and to object to processing based on legitimate interests (Art. 15 to 21 GDPR). Because the app uses only random identifiers, we usually cannot link data to you as a person; if you want us to delete something, please send us the installation ID shown in the app's Settings. You also have the right to lodge a complaint with a supervisory authority, for example the Berlin Commissioner for Data Protection and Freedom of Information (Berliner Beauftragte für Datenschutz und Informationsfreiheit, datenschutz-berlin.de).

7. Children

The app is not directed at children and does not knowingly collect personal information from anyone, including children under 16.

8. Changes

If this policy changes, the updated version will be published on this page with a new effective date. Material changes will also be announced in the app.

9. Contact

Caspar Baumeister · Dernburgstraße 7 · 14057 Berlin · caspar.baumeister.dev@gmail.com