Calibre Companion Android privacy notice

Updated September 15, 2026. Provided by Samuel Cohen. Contact sam.cohen94@gmail.com.

Library and connections

Books, covers, metadata, reading status and saved chats are stored on your device. The app connects to the calibre server or cloud account you select. Disconnecting does not delete cloud originals; revoke provider access through that provider. Files opened in reading apps are handled by those apps. Regular library features do not require an AI account.

Optional AI and Google sign-in

AI purchases use Google sign-in through Firebase Authentication. Google/Firebase processes your sign-in identity, including email, name and account identifiers. Our service verifies your identity and stores an account-linked credit balance, purchase verification records and usage records so purchases can be restored and usage charged correctly.

When you approve AI processing, your question, relevant conversation context, and selected book text or chapter content are sent over HTTPS through our Google Cloud service to OpenRouter and its selected model provider. Whole-book analysis can process text from multiple chapters. This is remote processing, not on-device AI. We request zero-data-retention routing and disallow provider data collection. Provider availability depends on those settings. Do not send content you do not want processed by these services.

We do not intentionally log book text, questions or answers. Recoverable answers are encrypted for your device and expire after 24 hours; automatic database cleanup may occur later. Local chats remain on your device until you delete them. Credit and transaction records do not contain book text. Hosting services process operational and security information such as IP addresses, request times and response status.

Purchases and retention

Google Play processes subscriptions and purchases. We receive purchase tokens, product identifiers, entitlement and order information to verify purchases, grant credits, acknowledge transactions, process refunds and prevent duplicate credit grants. We do not receive complete payment-card details. Account and billing records are retained while needed to operate the service and resolve transactions, security, fraud and legal obligations. Service providers apply their own retention rules.

Account and data deletion

Request deletion of your AI account and associated data. You can also request access, correction or deletion by emailing us. We verify ownership before deleting account data. Minimal records may be retained where needed for transaction accounting, fraud prevention, security or legal obligations. Signing out alone does not delete your account. Cancel subscriptions in Google Play to stop renewal.

Advertising and choices

When advertising is enabled, Google AdMob may process IP addresses and approximate location, device and advertising identifiers, ad interactions and performance information for advertising, measurement and fraud prevention. Google's User Messaging Platform manages applicable consent choices. Use Ad privacy choices in the app and Android's advertising-ID controls. Ad-free purchases remove in-app advertising; AI Plus is a separate subscription.

Optional crash reporting

Send crash reports is off by default. If enabled, Firebase Crashlytics receives crash, device and app information to diagnose failures. Disabling it stops automatic collection and requests deletion of unsent reports, not reports already received. This Android app does not enable Firebase Analytics or Firebase Messaging.

Support, international processing and local copies

Support email is used to answer your request and retained while needed for support, security and legal obligations. Google, OpenRouter and model providers may process information in other countries. Local data remains until removed through the app, Android storage controls or uninstalling; external files, backups, cloud originals and copies in other apps can remain. The app is intended for a general audience and is not directed to children under 13.

Provider notices: Google/Firebase, OpenRouter. The website and iOS privacy notice covers those separate services. This Android notice also covers the optional AI features described above.