hkd allows to define system-wide hotkeys independent from the graphical session, this means, that hotkeys will work in x11, wayland and even in a tty.
hkd only works on linux as it uses the linux-specific epoll and inotify APIs as well as the evdev interface for input recognition.
hkd doesn't require any libraries and has no dependency other than a standard C
musl should work too (altough I have not yet tested it).
make to compile,
make clean to remove the mess and
make debug to
compile a debug binary to use with gdb. To install run
make install and
make uninstall if you re done with it.
The man page is (at least in my opinion) pretty simple and explanatory, the program itself is very small (under 600 loc excluding comments and blanks) and the config file is documented trough an example. That said if I recive enough requests for further documentation I'll provide it.