Privacy Policy
1. Introduction
Bookstacks ("the App") values and respects user privacy. This Privacy Policy explains how information is collected, used, and disclosed in the App.
2. Information We Collect
2.1 User-Managed Information
The App stores the following information only on your device:
- Book information (ISBN, title, author, publisher, cover image URL)
- Label information (label names)
- Label assignments to books
- App settings (display mode, etc.)
Important: All this information is stored only on your device (local storage) and is never transmitted to external servers or the cloud.
2.2 External API Communication
To fetch book information, the App communicates with the following external services:
- OpenBD API (https://openbd.jp/): The App sends an ISBN to retrieve bibliographic information (title, author, publisher, etc.). Only the ISBN is sent; no personal information is included.
- OpenLibrary (https://openlibrary.org/): The App may use an ISBN to fetch cover images.
2.3 Camera
The App uses the camera to scan ISBN barcodes. Camera footage is used solely for barcode recognition and is never saved or transmitted.
2.4 Advertising Information
The App uses Google AdMob to display advertisements. AdMob may automatically collect:
- Device information (model, OS version, etc.)
- Advertising identifier (IDFA / Advertising ID)
- IP address
- App usage information
- Approximate location
This information is used for ad delivery, personalization, and effectiveness measurement.
3. How We Use Information
3.1 User-Managed Information
- Managing and displaying your book collection
- Showing book details
- Categorizing books with labels
- Persisting app settings
3.2 Advertising Information
- Displaying and delivering ads
- Ad personalization
- Measuring ad effectiveness
4. Information Sharing and Disclosure
4.1 User-Managed Information
Book and label information registered by users is never shared with third parties, including the developer. Everything is stored only on your device.
4.2 Advertising Information
Advertising identifiers and device information may be shared through Google AdMob for:
- Ad delivery to advertising networks
- Ad effectiveness measurement and analysis
For details, please refer to:
5. Data Storage and Deletion
5.1 Storage Period
User data is stored on the device until you uninstall the app or explicitly delete it within the app.
5.2 Data Deletion
- Books can be deleted individually from the detail screen
- Labels can be deleted from the label management screen
- Uninstalling the app removes all data
6. Security
User data is stored in local storage (Hive) on your device and protected by iOS's standard security features.
7. Children's Privacy
This app is not intended for children under 13. We do not knowingly collect personal information from children under 13.
8. Third-Party Services
This app uses the following third-party services:
- OpenBD API: Bibliographic data retrieval by ISBN (no personal data sent)
- OpenLibrary: Book cover image retrieval
- Google AdMob: Ad display (banner ads)
9. Changes to Privacy Policy
This Privacy Policy may be updated as needed. Significant changes will be notified through the app or GitHub repository.
10. Contact Us
For questions about this Privacy Policy:
- Email: bmf.infomation@gmail.com
Last Updated: March 10, 2026