With Web Services, the jobs outside SAP are :
1_ Define the Web Service in the application that will call SAP. The XML or JSON template shows the data that must be filled in.
2_ If it’s an export from SAP, you will have to modify the template file to show how to fill in the filters.
3_ If it’s import in SAP, you will have to explain how to fill each field of the template that the developer of the sending application understand how to use the Web Service. It’s important to define the field format and to provide the possible values.
For dynamic activities, it can lead to many data export from SAP to provide the complete info to the sending application.