Maxi,
Yes, it makes sense to use an export mapping to send a request to a REST service and an import mapping to receive the response. In the microflow, you’ll need to create the object(s) needed for the export mapping. Then you’ll use the objects you created in the Call REST action. This how to may be helpful: https://docs.mendix.com/howto/integration/consume-a-rest-service
Mike
Check below link...
https://medium.com/mendix/configuring-rest-services-in-mendix-a36c513df4b1
https://academy.mendix.com/link/modules/526/lectures/4134/2.3-The-Different-Methods
https://docs.mendix.com/refguide9/integration/publish-rest-service/