SAP Extensibility Services: Clean Core Extensions on SAP BTP

What Novarto delivers:

• Clean Core Extension Design: We assess your existing SAP customizations, identify which should be retired, which should be migrated to BTP, and which can be replaced by standard SAP functionality — then build the migration plan.
• SAP Fiori Application Development: Custom SAP Fiori apps and Fiori Elements extensions that improve usability for specific business roles, built using SAP Business Application Studio (BAS) and aligned with SAP UX guidelines.
• Side-by-Side Extensions on SAP BTP: Business logic and integrations that sit outside your SAP core, built using the Cloud Application Programming Model (CAP) and connecting to SAP S/4HANA through stable, published APIs.
• Backend Extensibility: OData service development, SAP HANA CDS views, and ABAP RESTful Programming Model (RAP) extensions for cases where in-system extensibility is appropriate without modifying the core.
• Cloud DevOps & Team Enablement: CI/CD pipeline setup for SAP BTP extensions, Cloud DevOps tooling, and knowledge transfer to your internal SAP team — so extensions remain maintainable after Novarto’s engagement ends.
• Fixed-Price Implementation Packages: For well-defined extensibility use cases, Novarto offers fixed-scope, fixed-price implementations — reducing budget risk for organizations with predictable requirements.

FAQ Section

1. What is SAP extensibility, and why does it matter for S/4HANA?

SAP extensibility refers to the methods available for adapting SAP systems to meet specific business requirements that are not covered by standard SAP functionality. In the context of SAP S/4HANA, extensibility matters because traditional modification of the SAP core — common in SAP ECC environments — creates upgrade risk and maintenance overhead. Every custom modification to the core must be reviewed, retested, and often rebuilt with each SAP upgrade cycle.

SAPs strategic answer to this is a layered extensibility model that distinguishes between in-app extensibility (adaptations made within the SAP system using published extension points) and side-by-side extensibility (custom applications and integrations built externally on SAP BTP). The goal is to keep the core SAP system clean and upgradeable, while still delivering the custom functionality the business needs, just outside the core rather than inside it.

2. What is Clean Core in SAP, and how does it affect customization?

Clean Core is SAPs architectural principle for S/4HANA that defines a clear boundary between the standard SAP system and any custom extensions. A clean SAP core means no custom modifications to SAP-delivered code — instead, all customizations use SAPs published extension points, BTP side-by-side extensions, or standard configuration. This allows SAP to upgrade the core system without breaking custom code, reducing the upgrade effort from months to weeks.

For organizations migrating from SAP ECC, where deep ABAP modifications were common, achieving Clean Core in S/4HANA typically requires a systematic assessment of existing customizations to determine what can be replaced by standard functionality, what should be rebuilt as a BTP extension, and what should be retired entirely. Novarto conducts this assessment as the first phase of its extensibility engagements, providing clients with a clear picture of their customization landscape and a recommended path to Clean Core compliance.

3. What is the difference between in-app and side-by-side SAP extensibility?

In-app extensibility covers adaptations made directly within the SAP S/4HANA system using SAP’s published, supported extension points, such as adding custom fields to standard screens, creating Fiori Elements apps based on SAP-provided APIs, or extending standard business objects using the ABAP RESTful Programming Model (RAP). These extensions stay within the SAP system but use only approved extension mechanisms, so they remain upgrade-compatible.

Side-by-side extensibility means building a separate application or service on SAP BTP that communicates with SAP S/4HANA through APIs, rather than modifying anything inside the SAP system itself. This is the right approach for complex custom logic, integration-heavy processes, or applications that require a user experience that cannot be delivered within SAP Fiori. Side-by-side extensions are fully independent of the SAP core, can be deployed and updated on their own lifecycle, and do not create any upgrade risk to the SAP system.

Novarto implements both models and advises clients on which approach is appropriate for each specific requirement. For more information, watch the videos below.