Flatpak developer demo application is a companion to the Flatpak developer documentation. It is an example of how to use Flatpak to build and distribute an application, and can be used as a reference implementation.

While the demo application uses Qt and the KDE runtime, the basic principles that it demonstrates are applicable to applications that use other runtimes and toolkits.

The application demonstrates the use of portals, showing how it is possible to securely access host functions like file choosers, notifications and screenshots. To do this, it uses the built-in support provided by the Qt toolkit. Similar support is also available for GTK.