particle Reader — Privacy Policy
Particle is an e-reader with a synced library, operated by an individual developer. This policy describes what data the Particle apps (iOS, Android, and the web library at particle-reader.com) and the Particle sync service collect, why, and what happens to it.
What Particle collects
- Account. An email address and a password, used only to sign you in. Authentication is handled by Supabase Auth; Particle's own servers never receive your password.
- Your library. The books you upload (EPUB and PDF files), their cover images, and book metadata such as title, author, identifier, and the original file name.
- Your reading data. Bookshelves, bookmarks, highlights and notes, reading positions and progress, per-book reading preferences, and your in-book search history — synced so you can pick up where you left off on another device.
- Sync bookkeeping. A per-device identifier, device name, platform, app version, and change timestamps, used to keep your devices in sync.
- Server logs and error monitoring. Standard technical logs (such as IP address, requested URL, and timestamps) are generated when you use the service, and server-side errors are recorded with technical details — the failing endpoint and the error, never request contents, your identity, or your IP address. Both are used only to operate and debug the service.
Crash reports (optional, off by default)
If you turn on Share crash reports in settings, a technical report is sent when Particle crashes: what went wrong in the code, plus device model, operating system, and app version. Reports never include your books, notes, reading activity, account details, or IP address — identifying details are removed on your device before anything is sent.
- Reports carry a random report ID (shown in settings) so you can link a support request to your own reports. It is not connected to your account and is deleted when you turn reporting off.
- Reports are processed on Particle's behalf by Sentry (Functional Software, Inc.) on servers in Frankfurt, Germany, and deleted after 30 days.
- Legal basis: your consent, which you can withdraw at any time by turning the toggle off. The app works identically either way.
What Particle does not do
- No analytics or tracking SDKs — the only diagnostic tool is the opt-in crash reporting described above.
- No advertising.
- No sale or sharing of your data with third parties for their own purposes.
Where your data lives
Particle uses three infrastructure providers, which process data on Particle's behalf to provide the service:
- Supabase — authentication, database, and file storage for your account and synced library.
- Fly.io — hosting for the Particle application and sync service.
- Sentry — server error monitoring and opt-in crash reports, on servers in the EU (Frankfurt, Germany).
All traffic between your devices and these services uses HTTPS.
Retention and deletion
Your data is kept for as long as your account exists. Deleting your account — available in the app's settings — removes your account and all synced data, including uploaded files. You can also request a copy of your data, or its deletion, by emailing the address below.
Children
Particle is not directed at children under 13.
Changes to this policy
If this policy changes, the updated version will be posted here with a new effective date. For material changes, notice will be given in the app.
Contact
Questions or requests about your data: support@particle-reader.com