ABAP on Cloud or ABAP Platform on BTP and S/4HANA Steampunk usage RAP - RESTful Application Programming Model to create managed and unmanaged scenario-based applications. The model is also available with SAP S/4HANA with embedded steampunk. You can create a HANA optimized Fiori based transactional application on SAP BTP ABAP Platform and Steampunk. The Clean Core on S/4HANA achievable using Side by Side extensions.