Source: modules/services/desktop/flatpak.nix Upstream documentation: Flatpak is a system for building, distributing, and running sandboxed desktop applications on Linux. To enable Flatpak, add the following to your configuration.nix: = true; For the sandboxed apps to work correctly, desktop integration portals need to be installed. If you run GNOME, this will be handled automatically for you; in other cases, you will need to add something like the following to your configuration.nix: = [ pkgs.xdg-desktop-portal-gtk ]; Then, you will need to add a repository, for example, Flathub, either using the following commands: $ flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo $ flatpak update or by opening the repository file in GNOME Software. Finally, you can search and install programs: $ flatpak search bustle $ flatpak install flathub org.freedesktop.Bustle $ flatpak run org.freedesktop.Bustle Again, GNOME Software offers graphical interface for these tasks.