How can I start an app in a different language in GNOME Builder


I’m working on the translation of a GTK/GNOME app.

While I can build and install it using flatpak-builder on my computer, I find that it’s not always as straightforward as using GNOME Builder.

Is there a way to launch an app in a different language using GNOME Builder?

Thank you.

This normally should be possible by adding the preferred language locale to the environment variable LC_ALL


$ LC_ALL=zh_CN.utf8 gnome-clocks

should open gnome-clocks in chinese locale.

How this is done in GNOME Builder is not clear. There is a way to add environment variables to the build environment, but I don’t see an option for adding environment variables to runtime environment, which is what is needed here.

@chergert: thoughts ?

You can add it as a finish arg to your flatpak manifest. e.g. Something like:

"command" : "my_app",
    "finish-args" : [

Will start the app in German, assuming you have the German locale installed with Flatpak.