Open source · GPL-3.0 · Android 10+

Your Proton data,
everywhere on Android.

ProtonSync brings your Proton Contacts and Proton Calendar into Android's native apps the dialer, lock screen, smartwatch, and every calendar app. No Google account required.

🔒 End-to-end encrypted 🌐 Two-way contacts sync 📱 Local-only storage
9:41🔋 ●●●
ProtonSync
👤 Contacts sync
📅 Calendar sync
ALAlice Miller
JDJonas Davis
SRSofia Reyes

Everything syncs. Nothing leaks.

Built for people who chose Proton for their privacy and want that same privacy on the rest of their phone.

Two-way contacts sync

Changes flow both ways between Proton Contacts and the Android Contacts provider. Add a contact anywhere, it's everywhere.

Calendar sync

Your Proton Calendar events appear in every calendar app on your phone, widgets included. Never miss a meeting again.

On-device E2E decryption

User, address, and calendar keys are unlocked locally. Decrypted data never leaves your phone unencrypted.

Local-only storage

Synced contacts and events are written only to Android's system providers no cloud backup of decrypted data, ever.

Sync logs

Built-in logging gives you full transparency into what was synced, when, and why. Debug everything yourself.

No tracking, no telemetry

Zero third-party analytics. No ads, no data mining. Just an app that does one job and respects you.

Syncing in three taps.

No complicated setup, no servers to configure. Sign in and flip a switch.

Sign in

Log in with your Proton account credentials. Keys are unlocked locally on your device.

Pick what to sync

Toggle Contacts, Calendar, or both. You're always in control of what gets synced.

Tap Sync Now

ProtonSync decrypts and writes to Android's native providers. Check the sync logs for details.

Privacy isn't a feature. It's the foundation.

Every design decision in ProtonSync puts your data's confidentiality first.

100%

Cryptography on-device. All key unlocking and decryption happens on your phone.

0

Third-party analytics or trackers included in the app.

GPL-3.0

Fully open source. Audit the code, open issues, or fork it it's yours.

Disclaimer: ProtonSync is not an official Proton app. It is an independent community project and is not affiliated with, endorsed by, or supported by Proton AG. Use it at your own risk.

Ready to set your Proton data free?

Grab the latest APK from GitHub releases, or build it yourself from source.

Find ProtonSync useful? Support its development ❤