Lumen collects no data. Here is exactly what happens on your device.
Lumen has no INTERNET permission in its Android Manifest. It physically cannot make network requests.
What Lumen does
- Your PDF files are read in place. They are never copied, uploaded, or moved.
- A search index (SQLite database) is stored in the app's private storage on your device.
- No analytics events are recorded.
- No crash reports are sent anywhere.
- The app has no INTERNET permission, so it cannot make network requests.
Permissions used
| Permission | Why |
|---|
READ_EXTERNAL_STORAGE (Android 8–12 only) | To read PDF files from the folders you select |
FOREGROUND_SERVICE | To run indexing in the background with a visible notification |
RECEIVE_BOOT_COMPLETED | To restart background sync after device reboot |
WAKE_LOCK | To keep the processor awake during indexing |
POST_NOTIFICATIONS (Android 13+) | To show the indexing progress notification |
No other permissions are requested or used.
Data on your device
- Search index (SQLite): stored in the app's private storage. Contains extracted text lines from your PDFs. Deleted automatically when you uninstall the app.
- Folder paths: the SAF URIs of folders you add to Lumen, stored in app preferences.
- Reading progress: the last page you viewed per document, stored locally.
Data sent off your device
Nothing. Ever.
Third-party SDKs
- ML Kit Text Recognition (Google): runs 100% on-device. No data is sent to Google servers.
- No analytics SDKs, no ad SDKs, no crash reporting SDKs.
Deleting your data
Delete the search index at any time from Settings → Delete Index. Uninstalling the app deletes the index and all app data automatically.
Contact
If you have questions about this policy, open an issue on the GitHub repository.