BookSlice

Privacy Policy

Last updated: September 2, 2025

The privacy of your data — and it is your data, not ours! — is a big deal to us. In this policy, we lay out: what data we collect and why; how your data is handled; and your rights with respect to your data. We promise we never sell your data: never have, never will.

1. What we collect and why

Identity and access

When you sign up for BookSlice or sign in with Google or Apple, we collect your name, email address, and profile picture from your Google or Apple account. We use this information to create and manage your account, personalize your reading experience, and communicate with you about our services. We may also send you optional surveys or contact you to help us improve our products.

Billing information

If you purchase a subscription or products for BookSlice, you will be asked to provide payment information and a billing address. Credit card information is submitted directly to our payment processor and does not hit our servers. We store a record of the payment transaction, including the last 4 digits of the credit card number, for purposes of account history, invoicing, and billing support. We store your billing address to calculate any sales tax due, send you invoices, and detect fraudulent transactions.

Product interactions and reading behavior

We store metadata about books you import (title, author, format, size) and your reading progress. Your books are stored locally on your device. To enable push notifications, we store the current chapter contents (or current page contents for PDFs). We collect detailed analytics about your reading behavior including:

  • Reading session duration and frequency
  • Books added, deleted, and reading progress
  • Chapter navigation and completion rates
  • Reading customization preferences (fonts, themes, colors)
  • Device orientation and reading patterns

AI feature usage

When you select text for AI explanations, we send the selected text snippet and surrounding context to our AI service provider. We collect:

  • Text selections and explanation requests
  • AI response times and error rates
  • Frequency and patterns of AI feature usage
  • Chat conversations with the AI assistant
  • Credit consumption per request for billing purposes
  • Usage history to provide detailed billing statements

AI provider data handling

Privacy is built-in by design for AI features:

  • No-Training Policy: We don't use any providers that train on data. Your inputs will never be used for training purposes by any AI provider.
  • Data retention: Providers may have their own data retention policies for compliance reasons. Important: Data retention does not imply training. We ensure that none of your inputs will be trained on by any provider.
  • Smart push notifications: Smart push notifications are designed with privacy in mind. Your notification data is handled securely without being used for training purposes.

Analytics and app usage

We use PostHog for analytics to understand how you use BookSlice and improve our services. This includes:

  • App screens viewed and navigation patterns
  • Feature usage and interaction metrics
  • Device information (OS version, app version, device model)
  • Performance metrics and error tracking
  • Anonymous usage patterns and trends

Analytics collected are minimal by default. You can opt out of analytics collection in the app settings.

Voluntary correspondence

When you email us with a question or ask for help, we keep that correspondence, including your email address, so that we have a history of past correspondence to reference if you reach out in the future.

2. When we access or disclose your information

  • To provide products or services you’ve requested.
  • To troubleshoot or fix a software bug, with your permission.
  • To investigate, prevent, or take action regarding restricted uses.
  • Aggregated and de-identified data for improving our AI features and understanding reading patterns.
  • To third-party service providers (Google for authentication, AI providers for AI features, PostHog for analytics).
  • When required under applicable law.

3. Your rights with respect to your information

  • Right to Know: You have the right to know what personal information is collected, used, shared, or sold.
  • Right of Access: You have the right to access your personal information and obtain information about its processing.
  • Right to Correction: You have the right to request correction of your personal information.
  • Right to Erasure: You have the right to request that your personal information be erased.
  • Right to Restrict Processing: You have the right to request restriction of how your personal information is used.
  • Right to Object: You have the right to object to the processing of your personal information.
  • Right to Portability: You have the right to receive your personal information and transmit it to another party.

To exercise these rights, please contact us at [email protected]. We may need to verify your identity before fulfilling your request.

4. How we secure your data

All data is encrypted via SSL/TLS when transmitted between your device and our servers. Your books are stored locally on your device. Authentication is handled securely through Google Sign-In. We implement industry-standard security measures to protect your account and reading data.

5. Data retention

We keep your account information and reading metadata for as long as your account is active. Analytics data is retained for up to 24 months. If you delete your account, we aim to delete your personal data within 60 days, though this may take longer in some cases. Books stored locally on your device are deleted immediately when you remove them from the app.

6. Your privacy controls

BookSlice provides two main privacy controls:

  • Analytics opt-out: Disable analytics collection in app settings
  • Data deletion: Delete individual books or your entire account and its associated data

7. Location of site and data

Our services are operated in Singapore and the US. By using our website or services and providing us with your personal information, you consent to this transfer.

8. Changes and questions

We may update this policy as needed to comply with relevant regulations and reflect any new practices. Whenever we make a significant change to our policies, we will update the date at the top of this page.

If you have any questions, comments, or concerns about this privacy policy, your data, or your rights with respect to your information, please contact us at [email protected].

Adapted from the Basecamp open-source policies / CC BY 4.0