Docker compose network issue…

Hi all,

I have a Ubuntu VM running an app in docker compose – the app is crAPI, something I am using for hacking APIs book.

I can access the crAPI app from the Ubuntu VM using 127.0.0.1:8888

However, I want to access the crAPI from another VM, for example a Kali VM on the same local network but I cant because the crAPI is using some 172 ip address. This seems to be some internal ip address accessible only from the Ubuntu VM, surely there is a way to make crAPI accessible on the network? 

I am well prepared and ready for some wacky commands to make this simple idea work.

Any ideas please?

Many thanks