How do I store my Threema Safe backup on my own server?

Threema Safe is available in Threema for Android and Threema for iOS. Threema for Windows Phone will add support for Threema Safe with an upcoming update.

Threema Safe can be used with any WebDAV server (such as NextCloud), provided that the server can be reached via the Internet and is equipped with a valid, trusted TLS certificate.

To support iOS clients, the server needs to be compliant with the ATS requirements.

Configure the server

  • Create a directory for Threema Safe on your WebDAV server, e.g., /path/to/threema_safe
  • In /path/to/threema_safe, create a text file, name it “config” (without filename extension), and add this content:
  • {
    "maxBackupBytes": 524288,
    "retentionDays": 180
    }
  • In /path/to/threema_safe, create a writable directory called “backups”

Please note that we cannot provide support for server setup and configuration.

Configure the app

  • Android:
    • In Threema for Android’s main view, open the side drawer, and select “My Backups”
    • Activate “Threema Safe”, and tap on “Expert Settings”
    • Deactivate “Use default server”, and enter the URL to your Threema Safe directory (as defined above), e.g., https://myserver.org/path/to/threema_safe. If your server requires HTTP authentication, please specify your username and password.
  • iOS:
    • In the “My ID” tab, select “Threema Safe”
    • Activate Threema Safe
    • Deactivate “Use default server”, and enter the URL to your Threema Safe directory (as defined above), e.g., https://myserver.org/path/to/threema_safe. If your server requires HTTP authentication, please specify your username and password.

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