Whether you are planning a move from SAP ECC6 to SAP Cloud ERP (S/4HANA) or have already completed the transition, adopting a Clean Core approach is key to gaining the full potential of your investment. It ensures your system remains stable, adaptable and ready to take advantage of ongoing innovation from SAP, without unnecessary complexity.
To help organisations take a structured first step, we have created a Clean Core Health Check. A short, focused engagement that clarifies what Clean Core means and outlines a practical roadmap to achieve it. You can find out more in our Clean Core Assessment flyer.
Before exploring how to achieve it, it is worth understanding what Clean Core really means.
When people talk about moving to SAP Cloud ERP (S/4HANA), the phrase clean core comes up a lot. But what does it really mean and why does it matter? Let’s break it down in simple terms.
What is the Core?
Think of the core as the heart of your SAP system. It’s where the essential ingredients live:
- Processes – the end to end steps that deliver business outcomes
- Data – configuration, master data and transactional data
- Integration – how SAP connects with other systems
- Operations – the behind the scenes work like monitoring, authorisations and release management
- Extensibility – ways you tailor SAP to fit your business needs
Over time, many ERP systems get cluttered with custom code, undocumented changes, and messy integrations. This makes upgrades painful, slows down innovation and drives up costs and delaying upgrades can lead to unsupported platforms. That’s where clean core comes in.
What is Clean Core?
Clean core is both a concept and an approach.
At its simplest, it means keeping your SAP system as close to standard as possible, while still giving you flexibility through the right kind of extensions and integrations.
A clean core is:
- Cloud compliant
- Governed by strong data and process standards
- Easy to maintain, upgrade and extend
It’s about balance: staying standard where you can and innovating outside the core where you need to.
Why Clean Core matters: the benefits
For customers, the benefits are clear:
- Upgrades become “non events” instead of big project
- New innovations from SAP can be adopted faster
- The system stays secure, stable and cost effective
- Full traceability across your core system
For users, the experience improves too:
- Faster, smoother processes with less complexity
- Cleaner, more reliable data for better decisions
- Business processes that are flexible but not chaotic
Goals and focus areas
So, what do we focus on to achieve Clean Core?
- Business Processes – standardise and simplify to reduce complexity
- Missing Key User Extensibility – decouple extensions from the standard system. For example:
- On stack extensibility: making safe extensions within S/4HANA using released APIs
- Side by side extensibility: building apps or workflows in SAP BTP without touching the core
- Data – ensure governed, compliant and consistent data
- Integration – use APIs and modern approaches like event based integration
- Operations – streamline, automate and monitor for efficiency
The Clean Core journey
Moving to clean core isn’t a one time project. it’s a journey. Typical steps include:
#1 Define the vision – agree on the principle: keep the core clean, innovate outside
#2 Assess your landscape – analyse custom code, processes and system health
#3 Create a roadmap – decide what stays, what goes and where extensions should live
#4 Establish governance – adopt SAP’s extensibility model and enforce clean development practices
#5 Reduce technical debt – retire unused code, shift enhancements to BTP and replace customisations with standard Fiori apps
#6 Modernise integration – move away from hard coded links to APIs and events
#7 Enable continuous innovation – adopt upgrades regularly, embrace automation and improve user experience with Fiori
#8 Upskill and adapt – train teams on clean ABAP and BTP and encourage a mindset shift: customisation in the core slows innovation
Levels of extensibility: from clean to risky
SAP defines different levels of extensibility:
- Level A – The cleanest option. Using SAP Build tools (on stack or side by side) with released APIs
- Level B – Still safe. Using classic APIs like BAPIs that are upgrade stable
- Level C – Risky. Accessing SAP internal objects not officially released
- Level D – Not recommended. Direct modifications, implicit enhancements or touching SAP tables
The rule of thumb: the higher the level, the riskier it gets for upgrades and long term stability.
Extensibility guidelines
To stay clean:
- Prioritise in-app and side by side extensibility
- Only use classic APIs where modern ones don’t exist
- Avoid internal objects and unsupported techniques
- Treat modifications as a last resort
Final thoughts
Clean core isn’t about stripping out everything unique to your business. It’s about being deliberate. You keep the heart of SAP standard and healthy and build your innovation in the right places – outside the core when possible.
That way, you get the best of both worlds: a system that’s stable and cost effective but also flexible enough to adapt as your business evolves.
