Is it possible to use Unity C# libraries in a outside C# project?

Hello.

I’m new to Unity and i’m currently working on creating my own multiplayer 2D game. After looking up different ways to implement the multiplayer part, i have decided to go with the built in network system in Unity.

However, i’m following the thought “Never trust the client” which means i want to develop the server program outside of the actual game for obvious reasons, hence the title of this question.

My question is, is it possible to use the Unity specific libraries in a outside project using Visual Studios, and if so, which files do i need and where can i find them?

Thanks in advance.

Yes you can. you usually need UnityEngine.dll or UnityEditor.dll or…
the following link explains external use for created dlls.