X Virtual Framebuffer (Xvfb) is a great quick application to run applications that expect a X11 server, but you don’t care to see the visual output.

To install:

sudo apt install xvfb

To run:

xvfb-run application

For more customization, I hear that it’s better to use xpra with Xdummy. I haven’t tried this myself yet, but if you experience issues with the application expecting randr or glx extensions, give it a shot.