Hi
@StefanSchnell1,
There's no REST API available, but you are able to expose any process or VBO as a SOAP web service by going to System -> Objects|Processes -> Exposure and then selecting "Expose a Business Object" or "Expose a Process".
There's also a command line tool, installed with Blue Prism, called AutomateC.exe that can be used to execute processes.
Lastly, each Runtime Resource exposes an HTTP interface that you can use to perform various actions against the specific runtime resource including kicking off a process on it.
You can find more information about all of the above in the online help.
Cheers,