Embracing the Clean Core Approach with SAP S/4HANA Extensibility


After completing this lesson, you will be able to:

  • Recognize the aspects of the clean core paradigm
  • Identify use cases for extension development

The Clean Core Paradigm


Given that standard SAP software cannot encompass all business processes, there is an ongoing need for new apps, reports, and functionalities. Traditionally, SAP partners and customers have built extensions on the SAP ECC system using ABAP code. However, with SAP S/4HANA and the customer's digital transformation journey towards the cloud, a more robust and loosely coupled extensibility model is required.

The Clean Core Paradigm

The clean core paradigm separates extensions from the core SAP app and connects to business objects through stable interfaces. This approach ensures smooth upgrades and extensions, preventing issues when moving from SAP S/4HANA on-premise to the Cloud. SAP aims to help customers expand their software with seamless updates using this concept.

By embracing the clean core paradigm, you can enjoy benefits like lower TCO, streamlined upgrades, less testing for users, and minimal adaptation for developers. It also enables IT providers to offer fixed-price upgrades, boosts innovation speed, accelerates SAP-delivered innovation adoption, supports quick response to changing business needs, and prepares organizations for cloud migration concerning custom extensions.

Overview: Extensibility Options

There are various scenarios how an SAP S/4HANA system can be extended. The following picture gives you an overview about the different scenarios for building SAP S/4HANA extensions and ideas, which technologies you can use for your business need.

Use Cases for Extension Development

In general you can decide between extending in the core of SAP S/4HANA or extending in SAP BTP:

SAP S/4HANA Customization

In SAP S/4HANA Cloud you can adapt or create your own user interfaces and business objects in two ways. You can use Key User Extensibility, which is a subset of tools that enables business users to extend the data model, business logic or UI of an SAP S/4HANA Cloud system. This is often used when you want to apply small changes such as hiding fields from specific users.

More information on Key User Extensibility

Another way of creating in app extensibility is to use Developer Extensibility. In comparison to Key User Extensibility a developer can create custom ABAP code on SAP S/4HANA Cloud, combining the benefits of custom ABAP code, with the required restrictions for cloud-readiness, and the SAP S/4HANA programming model to build SAP Fiori apps.

More information on Developer Extensibility.

BTP Side-by-Side Extensions

Side-by-side extensions refer to software applications that run externally to SAP S/4HANA Cloud, and interact with it using SAP standard APIs. Compared to in-app extensions, side-by-side extensions are not bound by the restrictions imposed within the core application.

In SAP Business Technology Platform you can choose between various ways of building loosely coupled extension applications. Business Users can build their extensions with the capabilities of the SAP Build portfolio.

More information on SAP Build Apps.

Developers can either develop Java and Node.js applications with the SAP Cloud Application Programming Model (CAP) or use the ABAP RESTful Application Programming model (RAP) to build services and SAP Fiori apps.

More information on CAP and RAP

By understanding these use cases and extensibility technologies, you can make informed decisions to create a tailored, efficient, and future-proof SAP S/4HANA extensibility model that aligns with your business needs and embraces the clean core approach.

In this learning journey, we will explore the integration of SAP S/4HANA Customization and BTP side-by-side extensibility. Our learning scenario will demonstrate how to extend an existing S/4 business process and incorporate new user groups into this process. Consequently, you will acquire the knowledge to use SAP S/4HANA key-user extensibility in conjunction with SAP Build Apps on BTP to achieve this objective.


Building extensions is a key pillar while working with SAP S/4HANA. To ensure seamless upgrades and migrations, the clean core paradigm methodology is introduced, which maintains a clear separation between the SAP application and extensions. SAP provides a range of extensibility technologies that follow this clean core paradigm.

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