There are 3 repositories under geometry-dash-private-server topic.
A fangame of Geometry Dash made in GameMaker:Studio 2
Sólo con agregar estos archivos a tu Geometry Dash Private Server tendrás control sobre las cuentas y moderadores de tu server. Absolute control over your GDPS (v0.9)
Just a GD server link editor
GMDprivateServer is an emulator of the Geometry Dash server, for which I have added some upgrades. like BetterCvoltonGDPS or GDOpenServer
"Source Code for the 1.6 GDPS. It's kinda disorganized cuz I did some dumb testing. Sorry. Also, the host sucks because they can't go 5 seconds without plastering invasive ads everywhere (which contradicts what they said about not having any invasive ads on their site)" - Flux3on
GeometryDash server emulator written in Java with using the Spring Framework