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:
```bash
sudo apt install xvfb
```
To run:
```bash
xvfb-run application
```
For more customization, I hear that it's better to use [xpra with Xdummy](https://xpra.org/trac/wiki/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.