flatpak-mask - Linux


Flatpak-mask manages Flatpak overrides for individual applications. Flatpak overrides allow modifications to the runtime used by an application, enabling isolation and customization of applications. It can be useful for testing, debugging, or providing custom configurations for specific applications.


flatpak-mask [OPTION...] [<COMMAND>]


  • -d, –default: Use the default runtime for the application (unmask)
  • -m, –mask: Mask the application by specifying a runtime
  • -r, –remove: Remove the mask for the application (unmask)


Masking an Application

Mask an application named "com.example.MyApp" to use the "com.example.runtime" runtime:

flatpak-mask -m com.example.MyApp com.example.runtime

Unmasking an Application

Unmask an application named "com.example.MyApp" to use the default runtime:

flatpak-mask -d com.example.MyApp

Removing a Mask

Remove the mask for an application named "com.example.MyApp":

flatpak-mask -r com.example.MyApp

Common Issues

Missing Runtime

If a specified runtime does not exist, Flatpak will report an error. Ensure the runtime you are attempting to mask to is installed.

Invalid Application ID

If an invalid application ID is provided, Flatpak will report an error. Verify the application ID before masking.



The flatpak-mask can be used in conjunction with other Flatpak commands to manage application overrides. For example:

  • flatpak update --user to apply overrides to user-installed applications
  • flatpak run --command=flatpak-mask to apply overrides from within a container

Related Commands

  • flatpak: Manages Flatpak packages and runtimes
  • flatpak search: Searches for installed Flatpak packages
  • flatpak info: Displays information about a Flatpak package or runtime