Privacy Policy

1. Principle: Data Minimisation

The CASify app and the website casify.website were built on the principle of data minimisation. We collect, process, and store as little personal data as possible.

Core principle: The CASify app works entirely without a user account, without login, and without an internet connection. All user data (favourites, settings, recently viewed content) is stored exclusively on the user's device and is never transmitted to external servers.

2. Controller

Lennart Koch
Further details about the controller, including the official address, can be found in the Legal Notice .
E-Mail: kontakt@casify.website

3. Data Collected and Purposes

3.1 CASify App (iOS)

The app itself does not collect any personal data. The following data is stored exclusively on the device:

• Favourites (bookmarks): list of saved chapter IDs
• Language setting: "de" or "en"
• Appearance: "light", "dark", or "system"
• Recently viewed content: list of recently opened chapters

This data is stored locally on the device via AsyncStorage. No data is transmitted to external servers. There is no analytics, tracking, or advertising.

Feedback & contact: The app includes a feedback button that opens the device's default email client (mailto link). No data is automatically transmitted to us. You decide whether to send the email.

3.2 App Store Purchase (Apple App Store)

When purchasing the app through the Apple App Store, payment data is processed exclusively by Apple. We only receive anonymised sales statistics without personal reference. The privacy policy of Apple applies.

3.3 Website casify.website

When visiting casify.website, the hosting provider collects technically necessary data:

• IP address (anonymised after 24 hours)
• Date and time of access
• Page accessed
• Browser and operating system (anonymised)

Hosting provider: IONOS SE, Elgendorfer Str. 57, 56410 Montabaur (ionos.de/terms-gtc/datenschutzerklaerung/) — their privacy policy applies.

Google Analytics

This website uses Google Analytics, a web analytics service provided by Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland. Google Analytics uses cookies to analyse the use of the website. Legal basis: consent pursuant to Art. 6(1)(a) GDPR. Consent can be withdrawn at any time via the cookie banner. Further information: policies.google.com/privacy

A visitor counter uses the browser's localStorage. This storage remains local on the user's device and is not transmitted to any server.

4. Legal Bases

Data is processed on the following legal bases under GDPR:

• Art. 6(1)(a) GDPR — Consent (Google Analytics)
• Art. 6(1)(b) GDPR — Performance of contract (app purchase)
• Art. 6(1)(f) GDPR — Legitimate interest (technical website logs)

5. Special Protection for Minor Users

The CASify app is aimed at upper secondary school students (ages 15–19). For this reason, we have taken special measures to protect underage users:

• No user account required
• No login
• No social media features
• No communication between users
• No collection of personal data within the app
• No advertising

6. Sharing Data with Third Parties

Personal data is not shared, sold, or rented to third parties. Exceptions:

• Apple: upon app purchase, subject to their privacy policy
• Hosting provider: technical server logs of the website

7. Retention Period

• App data (favourites, settings): until the app is uninstalled
• Website logs: in accordance with the hosting provider's policies (max. 90 days)

8. Your Rights (GDPR)

You have the following rights regarding your personal data:

• Right of access (Art. 15 GDPR)
• Right to rectification (Art. 16 GDPR)
• Right to erasure (Art. 17 GDPR)
• Right to restriction of processing (Art. 18 GDPR)
• Right to data portability (Art. 20 GDPR)
• Right to object (Art. 21 GDPR)
• Right to withdraw consent (Art. 7(3) GDPR)

To exercise your rights, contact: kontakt@casify.website

You also have the right to lodge a complaint with the competent supervisory authority. In Germany, this is the Federal Commissioner for Data Protection and Freedom of Information (bfdi.bund.de) or the data protection authority of your federal state.

9. Deleting App Data

Since all app data is stored exclusively on your device, you can delete it at any time:

• iOS: Settings → General → iPhone Storage → CASify → Delete App

10. Changes to this Privacy Policy

We reserve the right to update this Privacy Policy as needed. The current version is always available in the app under Settings → Privacy Policy and at casify.website. We will notify users via the app of any significant changes.

11. Data Protection Contact

For data protection enquiries:
Lennart Koch
E-Mail: kontakt@casify.website