Fastutle Modu Viewer

Modu Viewer Privacy Policy

Effective date Previous version

Modu Viewer (the “App”) is a viewer app that opens comic books (ZIP, RAR, 7z), PDFs and text and document files stored on your device. The App does not run any service or server of its own that you need to sign up for or sign in to. This policy explains what information the App handles and how.

1. Information stored only on your device

The following information is stored only on your device and is not sent to the developer.

  • Files you import and library information (titles, covers, reading position, bookmarks, reading settings)
  • App settings such as read-aloud settings, screen brightness and view mode
  • Google Drive sign-in token (encrypted and kept in the device’s secure storage)

Deleting the App also deletes this information. Backup files created by the App are saved to a location you choose, and the developer cannot access them.

2. Information collected and why

The App uses Firebase services provided by Google to improve the service and fix errors, and the information below is sent to Google.

Service Information collected Purpose
Firebase Analytics App usage events (importing, opening and deleting books, changing the reading mode, exporting and importing backups, failed Drive downloads, English words missing from the natural reading pronunciation dictionary), screen navigation, app instance ID, device information such as device model, OS version and language Understanding and improving how features are used
Firebase Crashlytics Error records when the App crashes (stack traces), device model and OS version, app version, app instance ID Analysing the causes of errors and improving stability
  • Book titles, file names and the text of error messages are not sent to Firebase. File contents are not sent either, with one exception: when you listen to a Korean book with natural reading, the App sends English words that are missing from its pronunciation dictionary, one word at a time. Each word is lowercased, a single word of at most 40 characters, and is sent only with the reading language, without the sentence, book title or file information; the same word is sent at most once per device and no more than 50 words a day. The words are used only to expand the pronunciation dictionary.
  • The App does not collect the advertising ID, and the App has no ads.
  • The information sent does not include anything that directly identifies you, such as your name, email address or phone number, and it is sent over an encrypted connection (HTTPS).
  • You can read how Firebase processes information in the Google Privacy Policy and Firebase Privacy and Security.

Sending an error log (only when you send it yourself)

If a file cannot be added to the library and you tap “Send a log to help fix this”, your mail app opens a message addressed to the developer (section 10 below). The message contains the file name and size, the number and types of entries inside an archive and the names of the first entries (up to 30), the error type and error message, the first lines of the call stack (up to 15), the app version, device model, OS version, language, and any description you write in the message. It is delivered only if you review it and send it yourself; if you do not send it, nothing is transmitted. Mail we receive is used only to find the cause of the error and is deleted once the issue is handled.

3. Google Drive integration

If you choose, you can sign in with your Google account and bring files from your Drive into the App.

  • The App accesses only the files you pick yourself in the Google file picker (drive.file). It cannot see your other Drive files or folder lists, and it does not modify or delete files.
  • Picked files are only downloaded to your device; the files and your account information are not sent to the developer’s server.
  • Drive integration is optional, and you can use all other features of the App without it.
  • You can revoke the App’s access at any time in your Google Account permissions. Sign-in information stored on the device is deleted when you delete the App.
  • The App’s use of information received from Google APIs complies with the Limited Use requirements of the Google API Services User Data Policy.

4. Device permissions

  • Internet: used for Drive integration, sending data to Firebase, downloading the natural voice model and opening the web page behind About › Licenses. Before it starts a feature that needs the internet, the app checks that it is connected by looking up this app’s website address (fastutle.com, or fastutlego.github.io in earlier versions); no personal information is sent in that check.
  • Notifications: shows playback controls as a notification while reading aloud.
  • Foreground service (media playback) and keeping the device awake: used to keep reading aloud while the screen is off.
  • Motion sensors: used for a visual effect on the library screen; sensor values are not stored or sent.
  • The App reads only the files you pick yourself in the file picker. It does not request permission to access your photos or all of your storage.

5. Reading aloud

Reading aloud is handled by the Android text-to-speech (TTS) engine installed on your device. The App does not send the text being read to the developer’s server. How the TTS engine you choose processes text is governed by that engine provider’s policy.

6. Disclosure to third parties

The developer does not sell your information or provide it to third parties for advertising purposes. Apart from the use of Google services described in sections 2 and 3, the error-log mail you send yourself, and the natural voice model download below, no information is sent outside the device.

  • Natural voice model download (optional): when you download the natural voice model, the App connects to Hugging Face’s servers (huggingface.co) to fetch the model files. Information needed for the connection, such as your IP address, reaches Hugging Face; the App’s content (such as book text) and personal information are not sent.

7. Retention and deletion

  • Information on the device is deleted when you delete the App or clear the App’s data.
  • Information sent to Firebase is deleted after a period of time under Google’s retention policies.
  • Please send requests for deletion, access and the like to the contact below. Because the App does not keep information that identifies you, we may ask for information needed to verify the request, such as your app instance ID.

8. Children’s privacy

The App is not directed at children under 13, and it does not knowingly collect information from children.

9. Changes to this policy

If this policy changes, we will post the changes and the effective date in this document.

10. Contact

Please send privacy questions to: