SEGW vs RAP for OData

Explanation

SEGW (Gateway Service Builder) generates a data provider class where you code CRUDQ operations manually. RAP (ABAP RESTful Application Programming) generates OData V4 services directly from CDS views with declarative behaviour definitions — much less boilerplate on S/4HANA.

Code example

@AbapCatalog.sqlViewName: 'ZVSO'define root view entity ZI_SalesOrder as select from vbak {  key vbeln, kunnr, netwr}

Real project scenario

A new Fiori dashboard was delivered in a week using RAP; the equivalent SEGW effort in a previous release took two.

Common mistakes

Building V2 SEGW services for new S/4 Fiori apps; ignoring authorisations in RAP behaviour definitions.

Best practices

Prefer RAP on S/4HANA; register services in /IWFND/MAINT_SERVICE; enable /IWFND/ERROR_LOG for diagnostics.

Interview angle

When would SEGW still be the right choice?