pcontacts

pcontacts signs in to your Proton Mail account, decrypts your contacts client-side using OpenPGP, and exposes them to the system Contacts app so they appear alongside your local contacts — the same way WhatsApp or Telegram surface their own contact directories.

This app is not affiliated with or endorsed by Proton AG.
It uses the same HTTP API as the Proton Mail web client, which is not officially documented or supported for third-party use.
The API may change at any time without notice.

Once contacts land in ContactsContract, the OS owns them.
Stock Android ships with pre-installed applications — Google Play Services, Google Contacts, Gmail, the OEM dialer, the OEM messaging app, vendor "assistant" services — that are granted READ_CONTACTS by default or are very difficult to revoke.
Decrypting Proton contacts onto a device with those apps still installed effectively shares them with Google and the OEM.
For a meaningful privacy posture, run pcontacts on a de-Googled ROM: GrapheneOS is preferred (sandboxed Google Play, per-app contacts scopes), or LineageOS for microG, or vanilla LineageOS without GApps.
pcontacts cannot fix this for you on stock Android; it is a property of the platform's permission model, not of this app.

Features:

• SRP login with TOTP two-factor authentication.
• Client-side-only decryption — your contacts are never sent anywhere except the system address book on your device.
• Full vCard field support: name, email, phone, address, organization, notes, instant messaging, photos, and group membership.
• Bidirectional sync: edits made in the system Contacts app are pushed back to Proton with end-to-end encryption.
• Soft-delete with a 1-hour grace period so accidental deletions can be cancelled before they reach the server.
• Per-field conflict detection when both the phone and Proton have changes to the same contact.
• Periodic background sync via SyncAdapter and WorkManager.
• No Google Play Services, no telemetry, no analytics, no tracking.

Source code: https://github.com/andreabenetton/pcontacts
License: GPL-3.0-only