Privacy Policy for BookStack

1. Information We Collect

1.1 Personal Information

BookStack does not collect any personally identifiable information such as:

• Name
• Email address
• Phone number
• Location data
• Contacts
• Identifiers linked to your identity

The app does not require user accounts or authentication. You are identified only by an anonymous, randomly generated identifier assigned by RevenueCat — we have no way to link this identifier to you personally.

1.2 Anonymous Usage Data

BookStack collects a limited set of anonymous, non-personal data to improve the app experience. This data is stored as subscriber attributes via RevenueCat and includes:

Onboarding preferences:

• Your selected reading goal (e.g. track books, build a reading habit)
• Selected pain points (e.g. forgetting books, messy notes)
• Whether you added a book during onboarding
• Notification preference (enabled, disabled, or skipped)
• Whether you completed the onboarding

In-app activity:

• Total number of books in your library
• The source from which a paywall was displayed (e.g. onboarding, settings)
• The type of plan purchased (monthly, yearly, or lifetime)
• Number of books at the time of purchase

None of this data is linked to your identity. It is used solely for improving the app, understanding user needs, and optimizing the experience.

2. Data Stored on Your Device

All reading-related data is stored locally on your device only and is never uploaded to our servers.

This includes:

• Book titles and authors
• Reading status (currently reading / finished)
• Reading dates (start and finish)
• Ratings, notes, and tags
• Custom book covers
• Photos of reading moments captured via the in-app camera
• App preferences

2.1 Camera Usage

BookStack uses your device camera for the following purposes:

• ISBN Scanning — to scan book barcodes and quickly add books to your library
• Reading Moments — to capture photos of moments while you read (e.g. your reading setup, a favorite page)

Camera access requires your explicit permission. Photos taken within the App are stored exclusively on your device and are never uploaded to our servers or shared with any third party. No images are processed, analyzed, or transmitted over the network.

Additionally, the App may cache publicly available book data (such as NYT Bestsellers lists) locally on your device for up to 24 hours to improve performance. This cached data contains no personal information.

This data remains fully under your control and is deleted if you remove the app.

3. Third-Party Services

BookStack uses a small number of trusted third-party services to provide core functionality.

3.1 Google Books API

• Used only to search for books and fetch book cover images
• Searches are initiated by the user
• No personal data is sent to Google
• No user profiles or identifiers are shared

Google's Privacy Policy: https://policies.google.com/privacy

3.2 RevenueCat (Subscription Management & Anonymous Attributes)

• Used to manage in-app purchases and subscriptions
• Processes anonymous purchase and subscription information
• Stores anonymous subscriber attributes as described in Section 1.2 (onboarding preferences and in-app activity data)
• All data is associated only with an anonymous RevenueCat identifier — no personally identifiable information is collected or stored
• BookStack does not have access to your payment details
• This data is not shared with any additional third parties beyond RevenueCat

RevenueCat Privacy Policy: https://www.revenuecat.com/privacy

3.3 Apple App Store

• Apple handles all payment processing
• Apple manages free trials, subscriptions, and refunds
• BookStack does not receive or store payment information

Apple Privacy Policy: https://www.apple.com/privacy/

3.4 New York Times Books API

• Used to display weekly NYT Bestsellers lists in the App
• Book data (titles, authors, descriptions, cover images, rankings) is fetched through our proxy server
• No personal data or user identifiers are sent to the New York Times or to our proxy server
• The proxy server does not log IP addresses or any personal data
• Data is cached for up to 24 hours on both server and device, then refreshed
• NYT data is not shared with third parties, resold, or used for any purpose other than display within the App

New York Times Privacy Policy: https://www.nytimes.com/privacy/privacy-policy

Bestsellers data provided by The New York Times.

4. What We Do NOT Collect

BookStack does not:

• Collect names, emails, or any personally identifiable information
• Use analytics or tracking SDKs
• Share data with advertisers
• Collect location data
• Collect device identifiers for tracking
• Collect health or sensitive data

The anonymous usage data described in Section 1.2 is used solely to improve the app and is never linked to your identity.

5. Data Sharing

BookStack does not share any user data with third parties for advertising, analytics, or marketing purposes.

6. Children's Privacy

BookStack does not knowingly collect data from children under the age of 13. Since no personal data is collected, the app is safe for general audiences.

7. Data Security

Your reading data (books, notes, ratings, tags) is stored locally on your device and is never uploaded to external servers. A limited set of anonymous usage data (described in Section 1.2) is stored securely via RevenueCat and is not linked to your identity.

8. Data Deletion

Since BookStack does not require an account, there is no account to delete. Your local data is removed when you uninstall the app.

If you wish to request deletion of the anonymous subscriber data stored via RevenueCat, please contact us at support@bookstack.sk and we will process your request.

9. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. Any changes will be reflected on this page with an updated date.

10. Contact Us

If you have any questions about this Privacy Policy or the app, you can contact us at:

📧 support@bookstack.sk