Flatpak, Snap and AppImage

In short: Flatpak, Snap and AppImage are cross-distribution ways of distributing programs. They bring their libraries along and so run the same on many systems.

In more detail: The price is more disk space and a somewhat slower start. In return you often get newer versions than in the distribution and isolation (sandbox).

In detail

• Flatpak: from the community around GNOME and Red Hat. Main source is Flathub. Command flatpak install flathub org.videolan.VLC. Sandbox with permissions (Flatseal to adjust). Preinstalled on Fedora and many desktops.
• Snap: from Canonical (Ubuntu). The Snap Store is central and belongs to Canonical. Packages update automatically. Also for server software. Criticised for closed store software and slow starts.
• AppImage: a single executable file you download and start (chmod +x). No installation, no automatic update, no sandbox by default.
• Comparison: distribution packages are lean and well integrated, Flatpak suits current desktop programs, AppImage is for “just try it quickly”.
• Security: Flatpak and Snap sandboxes limit access, but check permissions.

See also: Package management on Linux at a glance, Dependencies and libraries