Hata Defteri
Effective date: 14 October 2026
Privacy Policy
This policy explains how the Hata Defteri app handles your data. Hata Defteri is designed with a local-first approach: all your data stays on your device and is never sent to our servers.
1. About the App
Hata Defteri is an educational app that helps students photograph and save the questions they answered incorrectly, and learn them through spaced repetition. The app is developed by Bilgin Studios.
2. Data Controller
- Name: Ömer Bilgin
- Email: info@bilginstudios.com
- Website: bilginstudios.com
3. Data Collection and Storage
Hata Defteri does not collect personal data and does not send data to any server.
All user data is stored only on the user's device. The app does not send data to any server, cloud service or third party. Data stored on your device includes:
- Profile name (optional, entered by the user)
- Level, grade and exam information (selected by the user)
- Question photos and solution images
- Review history and statistics
- App settings and preferences
Data NOT collected:
- Phone number, email address or identity information
- Location data
- Device identifiers or advertising ID
- Usage analytics or behavioral data
- Crash reports
4. Camera and Gallery Access
The app uses camera and photo access solely for photographing questions and selecting question images from the gallery. Photos taken or selected are stored only on the device and are never sent to any server.
5. Children's Privacy
Hata Defteri is designed for students of all age groups, including primary, middle and high school. The app does not collect personal data, does not show ads, does not contain an ad SDK, does not include in-app purchases, does not track location, does not share data with third parties, and does not require an internet connection (all features work offline).
6. Third-Party Services
The app does not currently use any third-party analytics, advertising or tracking service.
7. Data Deletion
Users can permanently delete all their data using the profile deletion feature. Uninstalling the app also deletes all local data.
For more information, visit our data deletion page.
8. Policy Changes
This privacy policy may be updated. Changes are published on this page. Continued use of the app means you accept the updated policy.