Outbound call to virtual controller

Hello everyone, we are working on a student project connecting devices/roboter through a middleware and performing actions on them. However, we're new to robotstudio and the information is quite overwhelming. What we mainly want to do for now is to perform a virtual controller simulation triggered by an outbound call ( like f.e. REST-Call with a rest client or OPCUA channel) and later perform this on a real controller (YuMi). Is there something like an existing API, so RAPID code can listen to events and gets executed ? There is this Robot Web Services, but we aren't sure if this is the right approach. Are there also best-practices on how to perform actions based on outbound calls?
Thanks and best regards.