What host or origin does backend code run on?

I’m trying to use data hooks to keep some services in sync with each other and want to send data from Wix to my other service (an external application).

I think I’m running into trouble setting the correct security settings on my external service that will receive data from Wix via code running on my Wix backend.

I need to set the allowed hosts and origins in my external service and I was wondering if the velo code running on the backend is coming from a different host/origin than my main Wix website?