nixos-config/system/keyboard.nix

{ pkgs, lib, ... }:
{
  services.keyd = {
    enable = true;
    keyboards.default = {
      ids = [ "*" ];
      settings = {
        "main" = {
          # Some programs don't respect colemaks capslock bind, so we force it here
          "capslock" = "backspace";

          # keyd has incorrect defaults :/
          "leftshift" = "leftshift";
          "rightshift" = "rightshift";
          "leftalt" = "leftalt";
          "rightalt" = "rightalt";
          "leftcontrol" = "leftcontrol";
          "rightcontrol" = "rightcontrol";
          "leftmeta" = "leftmeta";
          "rightmeta" = "rightmeta";
        };
      };
    };
  };
}