Sending input from app to ue4 game. How?

I want to mirror input (such as mouse clicks and key presses…) from an external application, onto a ue4 game window.

Is there a way I can trigger mouse clicks and key presses in ue4? If I could do this, I could send the input to unreal via a client/server setup.

It is definitely possible - take a look at the Remote Control plugin in the engine. It does a lot of this already and you can either harness it or borrow some of the code implementation.

You can also get text from another program using Rama’s plugin: