ERP & S/4HANA
Clean Core in SAP S/4HANA
Finding the right balance between standard and extensibility
Imagine if you could reduce the complexity of your SAP system many times over – and achieve significant savings in the process. A so-called “clean core” can unlock considerable efficiency potential. In transformation projects, companies frequently report significantly fewer bespoke software customisations and a leaner system landscape, in some cases with up to 80% fewer modifications and a reduced database size. These figures merely illustrate part of the potential offered by a clean-core approach.
With the clean core approach, companies can not only drastically reduce the effort required for updates and maintenance, they also increase their flexibility for future enhancements and can respond more quickly to innovations. In a business world where technological changes and legal requirements are coming at companies at an ever-faster pace, the advantages are significant.
In this article, you will learn what a clean core is, why it is indispensable for SAP S/4HANA users in particular, and how you can future-proof your SAP system with a well-thought-out strategy and the right tools, such as the SAP Business Technology Platform (BTP). Find out how to keep your “digital core” clean while retaining the ability to expand.
Key points of the blog
What is a clean core?
What is a clean core?
Clean Core refers to a strategy that keeps the core of your SAP system clean and unchanged. Modifications and enhancements are made outside this core system, which significantly increases stability, maintainability, and flexibility. What does that mean in concrete terms?
- Clean documentation of all changes and enhancements
- Regular maintenance: Remove outdated customisations and keep your core lean
- Standardisation: rely on proven best practices to avoid redundant customisations
A clean core means that the core remains free of hard modifications and individual logic. This principle secures your release capability and ensures that future upgrades can be carried out without complications.
“Keep the core clean” – a principle that SAP has been following since the introduction of S/4HANA. – Björn Goerke, former CTO of SAP
Why is a clean core so important for SAP S/4HANA users?
Why is a clean core so important for SAP S/4HANA users?
A clean core enables not only technical advantages, but also strategic ones. Companies that use SAP S/4HANA can respond to changes more agilely and cost-effectively. Here is an overview of some of the advantages:
- Faster upgrades: Customisations remain external, which saves time when updates are performed.
- Automation: Around 70% of business processes can be standardised and automated.
- Leaner database: The database size can be reduced by up to 50%.
- Cost efficiency: Fewer customisations mean lower operating costs.
A clean core offers you the opportunity to adopt innovations and new functions more quickly. Would you like to know whether your company could benefit from a clean core? Check your current customisations: the more complex and numerous they are, the greater the potential benefits of a clean core strategy.
Finding the best clean core strategy
Finding the best clean core strategy
How do you achieve a clean core? There are two main strategies:
- A fresh start in the public (SAP Cloud ERP) or private cloud (SAP Cloud ERP, private): Ideal for new customers or companies that want a radical fresh start. In the public cloud, you rely entirely on the SAP standard, while the private cloud gives you more flexibility for customisations.
- Migration for existing customers: Many existing customers have implemented extensive customisations over the years, which are often so complex that upgrading becomes a problem. In this case, a gradual clean-up is helpful, removing outdated customisations and placing new enhancements outside the core.
Are you an existing customer? Then ask yourself the following questions: Are your systems currently release-ready? How much effort does your IT department invest in customisations? The answers to these questions will give you an indication of how urgent a clean core is for you.
How do you set up a clean core architecture?
How do you set up a clean core architecture?
A clean core does not happen overnight. It is the result of a conscious architectural decision and consistent processes. Here are a few steps to pave the way to a clean core:
Evaluate current customisations
Which modifications are necessary, and which can be removed?
Create a migration plan
How can existing customisations be outsourced to a side-by-side architecture?
Implement the new architecture
Define clear processes and guidelines to keep the core clean in the future.
Plan early and keep the long-term benefits in mind. A clean core requires a little more effort at the beginning but saves resources and costs in the long run.
Extension options in SAP S/4HANA
Extension options in SAP S/4HANA
A clean core does not mean that you have to forego all customisations. There are various ways to make enhancements without affecting the core:
- In-app extensions: Customisations directly in the cloud via key user extensibility. Ideal for smaller customisations that are SAP-compliant and maintainable.
- Side-by-side extensions via SAP BTP: Use the SAP Business Technology Platform to implement more complex extensions outside the core.
- On-stack extensions: Enable ABAP developers to enhance standard SAP processes with custom extensions that require close integration with the SAP S/4HANA backend, while keeping the digital core isolated from custom code.
The advantage of a side-by-side architecture lies in the fact that customisations remain independent of the core system and are less prone to issues during upgrades. By leveraging SAP Build and SAP AI Core / Generative AI Hub, these solutions automate processes, validate data, and integrate AI.
Practical tip
Practical tip
When planning an extension, ask yourself: Is this extension necessary for the entire business function, or could it also run externally? In many cases, a side-by-side architecture is the better choice.
How do you reconcile customisations and clean core?
How do you reconcile customisations and clean core?
The challenge for many companies is to maintain their individuality without “contaminating” the core. This is where SAP BTP, the Business Technology Platform, comes in. It enables extensions to be made outside the core while still integrating seamlessly with the SAP system.
- Use published APIs for all integrations
- Implement new customisations/extensions via the BTP instead of directly in the core system
- Maintain clean documentation and regularly review customisations
This strategy allows you to balance innovation and stability. Your IT remains flexible and your SAP system release-ready.
Best Practices für die Pflege eines Clean Core
Best practices for maintaining a clean core
A clean core must be maintained regularly. Here are some best practices:
- Regular system audits: Check your customisations for timeliness and relevance.
- Avoid direct individual customisations or even modifications: use side-by-side enhancements instead.
- Employee training: Familiarise your IT teams with the clean core principles.
- Use SAP BTP: The Business Technology Platform is the key to a sustainable extension strategy.
“SAP BTP gives us the flexibility we need to keep our SAP system stable and innovative in the long term.” – Katrin Wischhusen, KPS
Advantages of a clean core approach
Advantages of a clean core approach
A clean core saves costs, reduces complexity and ensures that your SAP system remains future-proof. The most important advantages at a glance:
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less effort for modifications
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processes can be standardised
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core business processes remain unchanged
By choosing a clean core, you benefit in the long term from simpler upgrades and better control over your system.
Reduced transformation effort
Transformations to the cloud, to SAP S/4HANA, or to other systems require less effort and lower costs when built on a clean core.
Improved custom code
Health checks of existing custom code ensure that future upgrades and changes can be implemented efficiently.
Easier compliance with standards
Establishing a governance board that manages changes and avoids unnecessary modifications.
Ability to keep the core clean
With the help of SAP BTP, you can keep the core clean to ensure a secure and robust system.
Faster innovation
Implement innovations smoothly, with high quality, flexibility, and cost efficiency.
Conclusion: The future belongs to Clean Core
Conclusion: The future belongs to Clean Core
A clean core is more than a technical decision – it is a strategic orientation. It enables you to keep your SAP system flexible and stable while fully exploiting the innovative power of SAP S/4HANA. With the support of KPS and SAP BTP, you can successfully implement this strategy.
Ready to take your SAP landscape to the next level?
You should therefore consider modernising your IT architecture using a clean core approach to achieve long-term efficiency. This will enable your company to respond agilely to new challenges and better position itself for the future.
Katrin Wischhusen
Managing Partner
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