I misunderstood it when I first shared it. Turns out it only works for commandline programs written in Python. That is unfortunate.

It says differently:

Whether you've built your application in Java, Node, or Haskell, or you just want to put a pretty interface on an existing tool like FFMPEG, Gooey can be used to create a fast, practically free UI with just a little bit of Python (about 20 lines!).

Don't want to write no stinkin' Python? Good news! Gooey is actually controlled entirely by a plain ol' JSON file. We're only using Python here because it has convenient bindings for generating the JSON.