What Clean Core Means and Why

Explanation

Clean Core means: no modifications, use released APIs only, prefer key user extensibility for tenant-scoped tweaks, developer extensibility for ABAP extensions inside the S/4HANA stack, and side-by-side (on BTP) for larger custom apps. Violations increase upgrade cost and block cloud migration.

Code example

" No code — use SAP Extensibility explorer to find released APIs and BAdIs

Real project scenario

A customer with 4000 modifications delayed their S/4 conversion by 9 months; a Clean Core assessment let them retire 60% before the project started.

Common mistakes

Believing 'we'll clean it later'; using unreleased APIs; hidden implicit enhancements on private includes.

Best practices

Register every new custom object with its extensibility type; run ATC with Cloudification variant; publish a Clean Core score.

Interview angle

Difference between KUX, developer extensibility and side-by-side.