OpenSMO++ is an opensource GPL3 free to use reimagination of the stepmania online server.
to compile it you need git and cmake.
git clone https://github.com/Tiny-Foxes/OpenSMOpp.git
cd OpenSMOpp
mkdir Build
cd Build
cmake -DCMAKE_BUILD_TYPE=Release ..
cmake --build .and it will put the executable in Releases.
if you find any issues contact me on dscord or make an issue report. :)