Threema's web client allows you to use Threema on the desktop without
compromising security.

  * Complete synchronization: By scanning a QR code, desktop and mobile
    device are connected at once, and all conversations are fully accessible
    on the desktop.

  * Security and data restraint: All communication between phone and PC is
    fully end-to-end encrypted. After the session is terminated, all
    synchronized messages are immediately deleted in the browser.

  * Open Source: Threema Web is open source and uses open standards. It is
    also possible to host Threema Web on your own server.

WWW: https://github.com/threema-ch/threema-web
WWW: https://threema.ch/en/faq/web_info