Tunnel only specific folder/directory with ngrok

This is quite late for you, but this might help others.

I came across this same situation and I found the way.

Basically you need to create virtual host as @TheDeadMedic have suggested and then you can use it for ngrok.

I found this tutorial for wamp, so you can get idea for XAMPP from it.

https://john-dugan.com/wamp-vhost-setup/

P.S. I’m not promoting this tutorial.