Install applications with Flatpak and Flathub

Flatpak installs applications isolated from the system, with their dependencies bundled, from a repository shared by every distribution: Flathub. Where dnf or apt provide the version validated by the distribution, Flatpak lets you install the latest version of an application without touching the system libraries, each application running in a sandbox. This guide shows how to add Flathub, then search for, inspect, install and update an application. For intermediate administrators, on every distribution. Two objectives of the RHCSA exam (EX200) deal with Flatpak: configuring access to repositories, installing and removing applications. Outputs recorded on 30 September 2026 on AlmaLinux 10, with Flatpak 1.16.0.

What you will learn

• The Flatpak model: sandbox and shared runtimes.
• Install Flatpak and add the Flathub repository.
• Search for and inspect an application before installing it.
• Install, list and update applications.
• When to prefer Flatpak over dnf/apt.

The Flatpak model

A classic package (dnf, apt) relies on the system libraries: its version therefore depends on that of the distribution. Flatpak reverses the model. Each application bundles everything it needs and runs isolated from the rest of the system. It no longer depends on the distribution, only on a runtime, a common base (for instance org.gnome.Platform) that several applications share to avoid duplicating everything.

In practice, installing an application also pulls its runtime the first time, then the following applications on the same runtime install in a few megabytes. Flatpak works in system mode (for everyone) or user mode (--user, without privileges).

Flatpak complements dnf and apt, it does not replace them

The core of the system (kernel, services, sshd, drivers) stays managed by the distribution's package manager. Flatpak targets desktop applications you want recent or that are missing from the official repositories. On a server, its use is marginal; it becomes useful as soon as a machine has a graphical interface.

Install Flatpak and add Flathub

Install the package, then declare the Flathub repository, the reference app store.

RHEL/AlmaLinux

sudo dnf install flatpak

Debian/Ubuntu

sudo apt update
sudo apt install flatpak

sudo flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
flatpak remotes -d

The --if-not-exists option makes the command replayable without error: run a second time, it exits with 0 without changing anything. flatpak remotes confirms that flathub is configured. Applications will now be searched for and installed from this repository.

Search for and inspect an application

flatpak search queries Flathub by keyword and returns the identifier of each application (in the form org.inkscape.Inkscape), which is then used to install it:

flatpak search inkscape

Inkscape   Vector Graphics Editor   org.inkscape.Inkscape   1.4.4   stable   flathub
Graphs     Plot and manipulate data se.sjoerd.Graphs        2.0.7   stable   flathub

Before installing, flatpak remote-info shows the size and the required runtime, without downloading anything:

flatpak remote-info flathub org.gnome.Calculator

        ID: org.gnome.Calculator
  Download: 1.9 MB
 Installed: 5.0 MB
   Runtime: org.gnome.Platform/x86_64/51

The application itself weighs a few megabytes; it is the runtime, pulled only once, that makes up most of the first installation.

Install, list and update

flatpak install downloads the application and, automatically, the runtime it depends on:

sudo flatpak install --noninteractive flathub org.gnome.Calculator

The output shows the cascading installation: the runtime, its graphics extensions, then the application.

Installing runtime/org.gnome.Platform/x86_64/51
Installing app/org.gnome.Calculator/x86_64/stable

flatpak list lists what is installed; the --runtime option isolates the shared runtimes:

flatpak list
flatpak list --runtime

Updating every application and runtime takes one command, to run regularly:

flatpak update

To remove an application, flatpak uninstall org.gnome.Calculator; flatpak uninstall --unused then cleans up the runtimes that no application uses any more.

Launch an application

An installed application is launched by its identifier:

flatpak run org.gnome.Calculator

flatpak run needs a graphical session

flatpak run opens a desktop application: it needs a display server (Wayland or X11). On a server without a graphical interface, the command has nowhere to display. Installation, search and updates, on the other hand, work perfectly from the command line on a headless server.

Flatpak or system package: which one to choose

Flatpak and the distribution's manager do not target the same software. The choice depends on the nature of the need.

Need	Tool
Kernel, services, sshd, drivers, command-line system tools	dnf/apt
Recent desktop application, or one missing from the official repositories	Flatpak (Flathub)
Version validated and integrated into the distribution	dnf/apt
Same application, identical across several distributions	Flatpak
Server without a graphical interface	dnf/apt (Flatpak's run would be useless)

Swipe to see more

On a RHEL server, the rule is simple: system software goes through dnf, and Flatpak only comes in for desktop use. The RHCSA exam mostly checks that you know how to add Flathub and install or remove a Flatpak application, not how to make it the server's main tool.

Key points

• Flatpak installs applications isolated from the system, with their dependencies, from Flathub.
• A shared runtime (e.g. org.gnome.Platform) serves as a common base: the first installation is heavy, the following ones light.
• The cycle fits in five commands: remote-add, search, install, list, update.
• flatpak remote-info inspects size and runtime before installing; uninstall --unused cleans up orphan runtimes.
• Flatpak complements dnf/apt for desktop applications; it does not manage the core of the system.

Knowledge check

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Knowledge check

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