KeyCastr

If you make screencasts or tutorials for a keyboard-driven app, KeyCastr stops you having to narrate every shortcut. Each keystroke appears as an overlay in a corner of the screen, so the viewer reads the chord at the moment the palette opens rather than listening to you spell it out. Live demos benefit for the same reason: nobody in the back row can see your hands.

The useful setting is the filter that shows only keys pressed with a modifier. Left on full display it renders everything you type, which turns a demo into a typing test and leaks anything you paste into a search field. The minimal visualiser, which draws just the modifier stack, is the one most people settle on.

It is free under a BSD licence with no tier above it, and it has been around since 2009, which is the reassuring part. The price you pay is a permission: KeyCastr only works if macOS is handing it every key event, so it needs Input Monitoring access. That is a reasonable trade for a recording session and an odd thing to leave switched on permanently — quit it when you are done.

Skip it if your recordings are mouse-driven, or if your capture tool already draws keystrokes.