Firmware in mechanical keyboards. QMK Configurator, QMK Toolbox and QMK CLI (command line interface) are used to program QMK. VIA Configurator software is used to customize QMK keyboards on the fly.

I recently picked up one of those cheap macropads (and wrote about it, of course). It is surprisingly handy and quite inexpensive. But I felt bad about buying it. Something like that should be easy to ...