# olausson.de Apps

> Independent, privacy-first tools for Proton users, made by Bjoern Olausson (BEO).
> Not affiliated with Proton AG. No analytics, no tracking, no telemetry; contact and
> calendar data stay end-to-end encrypted with your own Proton keys. Two products:
> Mail Checker for Proton Mail (a Firefox & Chrome extension) and Sync Provider for
> Proton (a native Android app for Proton Contacts & Calendar).

## Products
- [Mail Checker for Proton Mail](https://apps.olausson.de/mail_checker_for_proton/): a Firefox & Chrome browser extension to read, compose, reply to and manage Proton Mail from the toolbar without opening a tab. Multi-account, OpenPGP decryption, new-mail desktop notifications and an unread badge. Free, with an optional paid Pro tier. Install via Firefox Add-ons (https://addons.mozilla.org/addon/mail-checker-for-proton-mail/) or the Chrome Web Store (https://chromewebstore.google.com/detail/aapmapnnolfpdnmcekhofnjcnfpnbohp).
- [Sync Provider for Proton](https://apps.olausson.de/sync_provider_for_proton/): a native Android app that syncs Proton Contacts and Proton Calendar two-way into Android's own Contacts and Calendar providers, so they show up in Samsung/Google Contacts, Google Calendar, the dialer (with caller ID: name and photo on incoming calls) and on a watch. Proton offers no CalDAV/CardDAV, so apps like DAVx5 can't reach it; Sync Provider uses Proton's own API instead. Two-way sync of all contact fields, contact groups, photos, recurring events, reminders and attendees; contact filter rules to choose exactly which contacts sync, with a dry run that names every affected contact first; multiple accounts; local .vcf/.ics backups with optional encryption; beta support for Proton's post-quantum encryption keys (RFC 9980). Requires Android 10 or newer. Works on standard Android and on de-Googled / GrapheneOS devices without Google Play Services. Paid subscription with a 7-day free trial. Install via Google Play (https://play.google.com/store/apps/details?id=me.proton.sync), the Samsung Galaxy Store (https://galaxystore.samsung.com/detail/me.proton.sync), Uptodown (https://sync-provider-for-proton.en.uptodown.com/android) or Obtainium/GitHub (https://github.com/bolausson/sync-for-proton).

## Guides
- [Proton Mail notifications in the browser](https://apps.olausson.de/mail_checker_for_proton/proton-mail-notifications/): how Proton Mail's web notifications work, their limits, and how to keep getting new-mail notifications without keeping a tab open.
- [Proton Contacts on Android](https://apps.olausson.de/sync_provider_for_proton/proton-contacts-android/): why Proton contacts don't appear in Android's contacts app or show a name when someone calls, how to sync them into Android's own contacts database, where they then appear, and how to troubleshoot when they still don't show.
- [Proton, CalDAV/CardDAV & Android sync](https://apps.olausson.de/sync_provider_for_proton/proton-caldav-carddav-android/): why DAVx5 can't sync Proton, and the realistic ways to get Proton Contacts & Calendar onto Android.

## Key facts (as of 2026)
- Proton offers no native CalDAV or CardDAV, so standard clients such as DAVx5, Apple Calendar/Contacts and Thunderbird cannot sync Proton Calendar or Proton Contacts directly.
- Android reads contacts from one shared system database (the Contacts Provider). Proton's own Android apps keep contacts inside the app rather than writing to it, which is why Proton contacts do not appear in the phone's contacts app and why incoming calls from them show a bare number instead of a name. Caller ID is a lookup in that database, so no dialer setting can fix it; a sync adapter has to write the contacts there first.
- Once contacts are written into Android's shared database, no import step is needed: Google Contacts, Samsung Contacts, the dialer, messaging apps and a paired watch all read them automatically.
- There is no official Proton Mail browser extension. Proton Pass and Proton VPN ship official browser extensions; Proton Mail does not. Mail Checker for Proton Mail is an independent, unaffiliated extension.
- Both apps are independent and not affiliated with, endorsed by, or operated by Proton AG. "Proton", "Proton Mail" and "Proton Calendar" are trademarks of Proton AG.

## About
- Maker: Bjoern Olausson (BEO), an independent developer who uses both apps daily.
- Contact: mail+appsite@olausson.de
- Source / code: https://github.com/bolausson