flatpak

Flatpak is a framework for building, distributing, and running sandboxed desktop applications on Linux. It aims to be independent of distribution, enabling software to run across major Linux distributions by shipping apps in container-like bundles that share runtimes. Flatpak was initiated by Alexander Larsson at Red Hat and released in the 2010s as part of an effort to standardize Linux desktop packaging. Flathub is the best-known central repository for Flatpak apps, though additional remotes may be used.

Technical architecture: Each Flatpak package consists of an app image and one or more runtime images. Runtimes provide common libraries and system interfaces; apps reference a runtime instead of bundling duplicates. Flatpak uses OSTree for distributing and updating filesystem trees and supports atomic updates and rollbacks. Apps are sandboxed with Bubblewrap, restricting filesystem access and network, and they communicate with the host through portals for user dialogs, file pickers, and other integrations.

Usage: Users add remotes with flatpak remote-add, install apps with flatpak install, and run them with flatpak run. Updates are handled via flatpak update. The data for installed apps is stored under ~/.local/share/flatpak for user installations and /var/lib/flatpak for system installations. Flatpak can integrate with desktop environments through freedesktop portals and desktop launchers.

Reception and scope: Flatpak provides cross-distribution packaging, reduced dependency conflicts, and consistent updates, at the cost of larger app footprints and reliance on a central ecosystem. It is widely supported on major distributions and desktop environments; critics point to potential centralization, sandbox complexity, and occasional integration gaps with host systems. It competes with container-like packaging approaches such as Snap and AppImage.