RAP (RESTful Application Programming Model)RAP
What it is
SAP's standard framework for building transactional, OData-based services and Fiori apps in ABAP. You declaratively model a business object (CDS data model + behavior definition + behavior implementation) and RAP generates the OData service, draft handling, locking and ETag handling.
Why it matters for Clean Core
RAP is the modern, Clean-Core-native way to build SAP apps — it replaces BOPF, classic Web Dynpro and hand-written gateway code. Every new transactional ABAP app should be a RAP business object.
Common pitfall
Trying to learn RAP without first being comfortable with CDS view entities, associations and annotations. RAP assumes that foundation — a strong classic-ABAP dev who's weak on CDS bounces off RAP here.