Demo your shortcut keys on macOS

Ryan Hanson
Ryan Hanson
Published in
2 min readJul 28, 2021


To properly demo my apps, I need to communicate keyboard shortcuts, and a while back the only player in that game was the free, open source Keycastr. Unfortunately, Keycastr didn’t nail the visuals for me. The keyboard shortcuts are difficult to digest as a viewer, and the modifier key display is not prominent.

I think other developers had the same issues, and a couple more solutions popped up (SuperUser question). In normal circumstances, I would have purchased one of the other solutions and carried on working on my other apps. For demoing Charmstone, I was able to whip up Modkey in its entirety in a couple hours, so it felt silly to even think of purchasing one of the other, quite expensive options. Modkey only displays modifier keys, but it gave me the motivation to build a version that emphasizes keyboard shortcut display. Here’s a quick screenshot of what KeyLimePie looks like:

In case you didn’t follow that SuperUser question link, here’s the driving features behind KeyLimePie:

  • A free option (the watermark removal is a small one time in-app-purchase)
  • The ability to drag it to where I want
  • “Key” views that look fine in light and dark mode
  • Only show keyboard shortcuts by default, but optionally show all keystrokes (mainly to show modifier key presses)
  • Holding the modifier keys keeps the shortcut on the screen as long as I want.
  • Simplicity (I really just need to communicate shortcuts and don’t care for much else)
  • Mac App Store availability

For the initial version, all of the settings are available just in the menu bar, rather than a preferences window. Ideally, I will keep it that way — the slimmer the better for these types of apps in my opinion.

One more thing. KeyLimePie also has a keyboard shortcut log view. If you’re in a live demo, this is useful in the scenario where viewers might not have caught the last shortcuts that you executed.

Sometimes, as a developer (or maybe a Rectangle user), it can be useful to see the keycodes and modifier bit codes that belong to a keyboard shortcut as well.

That’s it! Now I have no excuses to procrastinate making a demo video for Rectangle’s website…