Sync Provider for Proton

BEO

In-app purchases

About this app

Sync your Proton Mail contacts and Proton Calendar events directly to your Android device — securely and automatically.

Sync Provider for Proton is an independent sync client that brings your Proton contacts and calendar events to your phone's native Contacts and Calendar apps. All data is protected with end-to-end encryption using OpenPGP, just like Proton itself.

KEY FEATURES
• Two-way sync — Changes made on your phone sync back to Proton, and vice versa
• End-to-end encryption — Your data is encrypted with your own keys before transmission
• Native integration — Contacts appear in your phone's Contacts app; events appear in your Calendar app
• Automatic background sync — Configurable intervals: 15 min, 30 min, 1 hour, 4 hours, or manual
• Secure authentication — SRP protocol with two-factor authentication (TOTP) support
• Contact groups — Proton labels sync as Android contact groups
• Full calendar support — Recurring events, reminders, attendees, and multiple calendars
• No tracking — Zero analytics, no ads, no third-party data sharing
• Battery friendly — Uses Android's native sync framework with configurable sync windows

WHAT YOU NEED
• A Proton Mail account (free or paid)
• Android 10 or later

SUBSCRIPTION
This app requires a monthly subscription. Subscription pricing is shown before purchase. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the current period. Manage or cancel your subscription anytime in Google Play Store > Account > Subscriptions.

PRIVACY & SECURITY
• All contact and calendar data is encrypted end-to-end using OpenPGP
• Your password never leaves your device (SRP authentication)
• Sensitive credentials are stored in Android's hardware-backed Keystore
• No data is shared with third parties — your data goes only to Proton's servers
• No analytics, crash reporting, or tracking SDKs

DISCLAIMER
This app is not affiliated with, endorsed by, or officially connected to Proton AG or any of its subsidiaries. "Proton", "Proton Mail", and "Proton Calendar" are trademarks of Proton AG. This app uses Proton's publicly available API to provide sync functionality.

SUPPORT
Questions or issues? Contact us at [e-mail] or visit https://apps.olausson.de

What’s new

Fixes events not syncing when their timezone used a deprecated name (e.g. some events from Business Calendar Pro). Timezones are now mapped to ones Proton accepts. Also: if an event still can't sync, you now get a notification listing which events and why, instead of it failing silently.