Privacy Policy

Effective Date: 19.01.2026

Last Updated: 19.01.2026

This Privacy Policy describes how Maximilian Kürschner ("we", "us", or "our") collects, uses, and protects your information when you use our cashbook mobile application (the "App").

1. Information We Collect

### 1.1 Information You Provide

When you use the App, you provide the following information:

  • Expense records: Amount, description, date, category, tags, and notes for each expense or income entry
  • User preferences: Settings such as locale preferences, viewing periods, and user-defined goals

### 1.2 Automatically Collected Information

  • Device information: Operating system version, device model, and app version (for troubleshooting purposes)
  • Usage data: Information about how you interact with the App (stored locally only)

### 1.3 Information We Do NOT Collect

We do not collect:

  • Personal identification information (name, email, phone number)
  • Location data
  • Contact lists or other device data unrelated to the App's functionality
  • Financial account credentials or payment card information

2. How We Use Your Information

We use the collected information solely to:

  • Provide core functionality: Store and display your expense records
  • AI-powered categorization: Send expense descriptions to our AI self hosted model to suggest expense categories
  • Improve user experience: Remember your preferences and settings
  • App functionality: Parse natural language input and provide analytics

3. Data Storage and Security

### 3.1 Local Storage

All your expense data is stored locally on your device in an encrypted SQLite database. We do not transmit your expense data to our servers or any cloud storage service.

### 3.2 Third-Party Services

The App uses the following third-party service:

<!-- - Ollama AI Service: When you create an expense entry, the description text may be sent to our self hosted Ollama model to automatically suggest a category. No other personal or financial data is transmitted. -->

  • OpenAI API: When you create an expense entry, the description text may be sent to our self hosted OpenAI API to automatically suggest a category. No other personal or financial data is transmitted.
  • Posthog: We use Posthog to analyze user behavior and improve the app. No personal data is transmitted. Posthog processes this data according to their own privacy policy.

### 3.3 Data Security

We implement industry-standard security measures:

  • Data is stored locally on your device with iOS/Android platform-level encryption
  • No data transmission to external servers (except AI categorization as described above)
  • You maintain full control over your data through device-level security (passcode, biometrics)

4. Your Rights Under GDPR

If you are located in the European Economic Area (EEA), you have the following rights:

  • Right to Access: You can view all your data within the App at any time
  • Right to Rectification: You can edit any expense record or setting directly in the App
  • Right to Erasure: You can delete individual expense records or all data by uninstalling the App
  • Right to Data Portability: You can export your data (feature available in app settings or upon request)
  • Right to Object: You can disable AI categorization in app settings
  • Right to Withdraw Consent: You may stop using the App at any time

To exercise these rights, contact us at mail@maximilian-kuerschner.de.

5. Data Retention

  • Expense data: Stored locally on your device indefinitely until you manually delete it or uninstall the App
  • App settings: Retained until you reset them or uninstall the App
  • Deletion: Uninstalling the App permanently deletes all locally stored data from your device

6. International Data Transfers

Since all data is stored locally on your device, there are no international data transfers except:

  • AI categorization requests sent to OpenAI API <!-- our self hosted Ollama model -->

7. Children's Privacy

The App is not intended for children under 16 years of age. We do not knowingly collect information from children under 16. If you believe a child has provided us with personal information, please contact us at mail@maximilian-kuerschner.de.

8. In-App Purchases

If you make in-app purchases or subscribe to premium features:

  • Payment processing is handled by Apple App Store or Google Play Store
  • We do not collect or store your payment information
  • Subscription and billing data are managed by Apple/Google according to their privacy policies
  • Your purchase history may be stored locally for feature access verification

9. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by:

  • Posting the new Privacy Policy in the App
  • Updating the "Last Updated" date at the top of this document
  • Providing an in-app notification for material changes

Your continued use of the App after changes constitutes acceptance of the updated Privacy Policy.

10. Your Consent

By using the App, you consent to this Privacy Policy and our collection and use of information as described herein.

11. Contact Us

If you have questions about this Privacy Policy or wish to exercise your rights, please contact us:

Email: mail@maximilian-kuerschner.de

Data Controller: Maximilian Kürschner

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This Privacy Policy is compliant with the General Data Protection Regulation (GDPR) and Apple App Store/Google Play Store requirements.