How to get domain adress for REST API request

It’s a rest api (angular + spring boot) application. I understand that bseUrl is related to my app but I want to make a rest api call based on the instance on which the app is isntalled so i don’t think this is the solution.
I want to get the “your-domain” from the instance on which the app is installed. this is how i understand it

here is my second issue with that which describes how the app looks like: How to store company context in external storage