Guide
What is SAP Clean Core?
Clean Core is SAP's principle that your business system should stay close to the standard — extended through released, stable interfaces rather than by modifying SAP's own code or writing directly against its database tables. A clean core can be upgraded, run in the cloud, and adopt new SAP features without the custom code breaking.
It doesn't mean "no custom code." It means custom code that sits in the right place and only touches what SAP has officially released — so an upgrade is a routine event, not a project.
The 3-tier extensibility model
Clean Core organizes extensions into layers, keeping the standard core untouched.
Key-user extensibility
In-app, no-code/low-code adaptations — custom fields, logic and Fiori (modern web UI) tweaks made by business power users, no developer required.
Developer extensibility
On-stack ABAP Cloud (SAP's cloud-safe development model) using released APIs only — RAP, CDS and clean OO ABAP. Where most custom business logic should now live.
Side-by-side extensibility
Decoupled apps and services on SAP BTP, integrated through released APIs and events — for logic that shouldn't sit in the core at all.
The business case in three lines
Upgrades stop hurting
When custom code only uses released APIs (SAP's official, upgrade-safe interfaces), SAP upgrades and feature packs apply cleanly — no modification adjustments, no regression firefighting.
Lower risk & cost
A clean core means less custom code to test, fewer surprises, and a smaller, well-understood surface to maintain — lower total cost of ownership over the system's life.
Cloud & innovation ready
Released APIs, RAP (SAP's modern app framework) and side-by-side extensions are the on-ramp to S/4HANA Cloud, BTP (SAP's cloud platform) and the latest SAP innovations.
How you get there
You don't rewrite everything. You measure your gap (ATC, SAP's code-quality checker, plus a readiness audit), adopt the cloud-safe building blocks today, and migrate the rest — old reports rebuilt on SAP's modern stack (CDS/RAP/Fiori), brittle screen-automation (BDC) swapped for released APIs — module by module, at a pace the business can absorb.
Ready to start your Clean Core journey?
Book a free 30-minute scoping call. We'll look at your landscape and show you the fastest, lowest-risk path to a clean S/4HANA core.