Privacy Policy

Last updated: October 23, 2026

1. Introduction

Readium ("we", "our", or "us") operates the Readium mobile application (the "App"). This Privacy Policy explains what information we collect, how we use it, and your choices regarding your data.

2. Information We Collect

Information you provide

  • Imported content: Books, PDFs, and articles you import are stored locally on your device. We do not access, read, or store your imported content on our servers unless you explicitly use the PDF extraction feature (see below).
  • Account information: If you subscribe to Readium Premium, your subscription is managed entirely through Apple App Store or Google Play Store. We do not collect your payment information directly.

Information collected automatically

  • Crash reports: We use Firebase Crashlytics to collect anonymous crash reports to improve app stability. These contain device type, OS version, and stack traces - no personal content.
  • App analytics: We use Firebase Analytics to understand app usage, including onboarding, imports, playback, and feature usage, and to improve Readium.
  • Advertising measurement: We use Meta App Events to measure app installs and sessions resulting from our Facebook and Instagram campaigns. The SDK sends app event and device information to Meta. On iOS, access to your advertising identifier is enabled only if you allow tracking through Apple's permission prompt. Readium does not send your book titles, document text, library identifiers, or reading history to Meta.
  • PDF extraction: When you use the PDF import feature, your PDF file is uploaded to our server so its text can be extracted. The file is processed in memory and discarded as soon as extraction completes; only the extracted text is returned to your device. We do not persist or retain the file or its contents on our servers.

Information we do NOT collect

  • We do not send your books or document contents to analytics providers.
  • We do not request access to your device's precise location.
  • We do not display advertisements inside Readium.
  • We do not sell your data to third parties.

3. How We Use Information

  • To provide and maintain the App's functionality.
  • To process PDF files for text extraction when requested by you.
  • To diagnose crashes and improve app stability.
  • To understand app usage and measure our advertising campaigns.
  • To manage your subscription status (via App Store / Play Store).

4. Data Storage & Security

Your library, reading preferences, and bookmarks are stored locally on your device using platform key-value storage (MMKV), which is protected by the operating system's standard app sandboxing and file protection. PDFs uploaded for extraction are processed in memory on Google Cloud Platform servers (US region) and are not persisted after extraction completes.

5. Third-Party Services

The App uses the following third-party services:

  • Firebase Crashlytics (Google) - anonymous crash reporting. Privacy Policy
  • Firebase Analytics (Google) - app usage analytics. Privacy Policy
  • Meta App Events - app install and session measurement for Facebook and Instagram advertising. Privacy Policy
  • Apple App Store / Google Play Store - subscription and payment processing.
  • Microsoft Edge TTS — premium text-to-speech voice synthesis. The text of the passage you're listening to is sent so it can be turned into audio with word-level timing. No account identifiers are attached to those requests.

6. Children's Privacy

The App is not directed at children under the age of 13. We do not knowingly collect personal information from children under 13.

7. Your Rights

You can:

  • Decline tracking when asked on iOS, or change your choice in Settings → Privacy & Security → Tracking. Readium remains available regardless of your choice.
  • Delete all your local data by uninstalling the App or clearing app data in your device settings.
  • Cancel your subscription at any time through the App Store or Play Store.

8. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last updated" date.

9. Contact Us

If you have any questions about this Privacy Policy, please contact us at: support@readium.zohodesk.com