Exploring the SAP S/4HANA Cloud Extensibility Model

This lesson explains the various extensibility options for SAP S/4HANA. These include key user extensions, classic extensions, developer extensions, and side-by-side extensions, each serving different requirements and use cases.

This extension option enables business users to make customizations and enhancements directly in the SAP application. This is useful for quick customizations that do not require in-depth technical knowledge.

Key User Extensibility is the easiest way to extend functionality in SAP S/4HANA Cloud. The idea is to realize the different possibilities of extension through apps.

This type of development is intended for citizen developers. The SAP code cannot be accessed. This approach therefore fulfills the dogma of "Keeping the Core Clean Strategy."

The following functionalities can be used through key user tools in the SAP S/4HANA Cloud, SAP S/4HANA:

• UI Adaptation
• Custom fields
• Business Logic
• Custom Business Objects
• Custom UI

The blue part is the core. The green extensions are the Key User Extensibility parts. You can see that you can expand at almost every level.

The green area on the far left can be created using custom business objects (I5) as well as with the ABAP RESTful application programming model.

The showing figure shows the creation of custom fields with key user tools in an SAP S/4HANA:

As already mentioned, the most important tools for user extension are designed for SAP S/4HANA Cloud, but are also made available for SAP S/4HANA private edition and on premise. Here are some differences:

• Different UI/OData (gateway) setup (embedded vs. hub scenario).
• Different setup of identity and access management (IAM) and communication management.
• Different transport setup (between Dev, Q and P systems).

Blogs and help pages

• The Key-User Extensibility Tools of S/4 HANA
• Extensibility - ABAP Platform
• S/4HANA Extensibility: Use Case Overview
• SCN S/4HANA Extensibility: Scenario Diagrams
• S/4HANA Extensibility Concept Details: Restricted ABAP
• BAP Extensibility Community
• Help Portal - Key-User Extensibility
• Help Portal - SAP S/4HANA Cloud
• In-App Extensibility Overview
• SAP Fiori for SAP S/4HANA - What is Key-User Extensibility and Who are your Key-Users
• SAP S/4HANA Cloud, public edition, Examples
• SAP Extensibility Explorer for SAP S/4HANA Cloud

Videos

• Key-User Adaptation
• Extensibility and Custom Fields
• Extending Fixed Assets Master Data in SAP S/4HANA Cloud
• Creating Custom Fields
• Creating Custom Applications
• Implementing Business Logic

Trainings and Books

• Schneider, Thomas; Wolf, Werner: Extensions for SAP S/4HANA (in German) SAP PRESS 2018. (in German)

Documentation

• Key-User Extensibility
• Key-User Extensibility Tools in SAP S/4HANA (OP/PCE):
• Key-User Extensibility
• Adapting SAP Fiori UIs at Runtime - Key-User Adaptation - SAP Help Portal
• Fiori Apps Library

This traditional enhancement method involves customizing the SAP code directly in the system. This offers a high degree of flexibility, but can also lead to challenges with updates and maintenance.

Classical enhancement in the ABAP stack is only recommended in exceptional cases. Therefore, this is not the extensibility approach in our example.

Classic extensibility (done using Classic ABAP) is available in SAP S/4HANA Cloud private edition and an SAP S/4HANA on-premise deployment. SAP S/4HANA Cloud public edition and SAP BTP ABAP environment use ABAP Cloud only. Classic extensibility refers to the broad range of SAP's traditional and historical extensibility options that you as a customer or partner can use to extend ABAP-based on-premise SAP solutions.

Classic Extensibility incorporates all development paths before the introduction of ABAP RESTful application programming model. You can see that ECC systems can only be extended via Classic extensibility.

As shown in the previous figure, you can create custom applications (yellow components) that are be clean core compliant. However, the core can also be extended (green components), which would not be clean core compliant.

The following list is a comparison of Classic Extensibility with Developer and Side-by-Side Extensibility:

• https://help.sap.com/viewer/p/SAP_S4HANA_ON-PREMISE -> Product Assistance -> English -> Enterprise Technology -> ABAP Platform (or SAP NetWeaver in older releases) -> Developing on the ABAP Platform -> Development Concepts and Tools -> Extensibility -> Classic Extensibility

• The SAP Community Network, ABAP Extensibilitytopic page is the landing page for ABAP Extensibility-related topics.

• SAP S/4HANA Extensibility Options For Clean Core Journey

• Extend SAP S/4HANA in the cloud and On Premise with ABAP based extensions

• [ABAP Cloud - Technical Use Cases and Recommended Technologies] (ABAP Cloud - Technical Use Cases and Recommended Technologies.)

Developers have the option of making advanced customizations and extensions that go beyond the key user options. This requires in-depth technical knowledge and offers extensive customization options. The ABAP RESTful application programming model (as an essential part of ABAP Cloud) is supported on all SAP S/4HANA deployment options.

Developer Extensibility allows customers to implement extensions while simultaneously maintaining a clean core. Frameworks and concepts are developed for this purpose. Developer extensibility is accomplished through released ABAP RESTful application programming model extension points and/or through released BAdIs.

ABAP RESTful application programming model is a set of concepts, tools, languages, powerful frameworks, and best practices provided on the ABAP platform. The ABAP RESTful application programming model enables the efficient and rapid development of innovative and cloud-enabled enterprise applications as well as for the extension of SAP standard applications in the cloud and on-premise. It is deeply integrated into the ABAP language and is an essential part of ABAP Cloud. Also, ABAP development tools for Eclipse have been optimized to support the development process. The most important building blocks in the ABAP RESTful application programming model are:

• Core Data Services (CDS), which are used for SAP HANA-optimized queries to define semantically rich data models for all application domains and to define the transaction behavior of the modeled entities.
• The modernized and extended ABAP language, which is used to implement business logic.
• The OData protocol, which is used for stateless communication.
• The concept of the business object (BO), which is used to build transactional, analytical and integration oriented applications.
• The concept of the business service, which is used to define services.

ABAP RESTful application programming model provides a standardized development flow in ADT and a rich feature set for building applications from different domains, either from scratch or by reusing existing custom code.

Various types of consumable services can be created with the ABAP RESTful application programming model:

• OData-based services for building role-based and responsive SAP Fiori apps.
• OData-based services for exposure as Web APIs.
• Business events.

The ABAP RESTful application programming model is supported on all SAP S/4HANA deployment models and SAP BTP ABAP environment.

The enhancement tools are available for developers in both the SAP S/4HANA public edition and SAP S/4HANA private edition | on-premise. However, there are some differences.

• Different UI/OData (gateway) setup (embedded vs. hub scenario).
• Different setup of identity and access management (IAM) and communication management.
• Different transport setup (between development, test and production systems.)
• This means that tools work differently in some areas (for example, OData publishing and UI) or are not available at all in SAP S/4HANA (for example, ADT editors for Cloud IAM/COM). Refer to the documentation for Public Cloud and SAP S/4HANA.

The following blogs provide an overview of Developer Extensibility in the context of the various environments:

• https://blogs.sap.com/2021/09/30/steampunk-is-going-all-in/.
• https://blogs.sap.com/2022/09/05/embedded-steampunk-some-more-details-for-abap-developers/
• https://blogs.sap.com/2022/12/22/abap-cloud/
• https://blogs.sap.com/2022/10/25/how-to-use-embedded-steampunk-in-sap-s-4hana-cloud-private-edition-and-in-on-premise-the-new-abap-extensibility-guide/
• https://blogs.sap.com/2023/05/24/abap-cloud-what-does-it-comprise/
• https://blogs.sap.com/2023/05/26/abap-cloud-sap-s-4hana-extensibility-may-2023-update/

Documentation

• Developer Extensibility
• ABAP Cloud - Technical Use Cases and RecommendedTechnologies
• UI Development
• UI Technologies

Learning Journeys

Develop Extensions Using SAP S/4HANA Cloud, ABAP Environment

Tutorials, Best Practices, How-Tos

• SAP S/4HANA Cloud ABAP Environment | SAP Community
• SAP Extensibility Explorer for SAP S/4HANA Cloud
• SAP Extensibility Explorer for SAP S/4HANA Cloud
• Create Your Own Gadget Shopping App Using Developer Extensibility
• Enrich Your Gadgets Shopping Application With Developer Extensibility Reuse Services
• Extend SAP S/4HANA Manage Purchase Orders SAP Fiori App with Custom Fields

With this method, extensions are developed and integrated outside the SAP system specifically on SAP BTP. This enables flexible customization without direct changes to the core system, which simplifies maintenance and upgrades.

This approach offers many different options. One common feature is the use of released APIs from SAP S/4HANA Cloud. These APIs are used to perform CRUD operations on SAP S/4HANA Cloud data. Different concepts, tools, and services are able which can use these remote APIs.

Side-by-side extensions are software applications that run outside of SAP S/4HANA Cloud (or another business application) but interact with it via standard SAP APIs.

They can potentially run on any runtime application platform, but SAP offers and recommends the SAP Business Technology Platform.

The following image shows an overview of the different side-by-side extension options.

• Proxy applications for a separate target group (no ERP users).
• Convenient applications that should run separately from the ERP.
• A customized application that runs in parallel with ERP to reduce the load on the operational system.
• Customized applications that require proximity to intelligent SAP BTP services such as machine learning, AI, and so on.
• Replacement apps that integrate with various ERP and cloud services.
• Partners want to offer a SaaS solution and therefore need to operate their service independently of the SAP S/4HANA system.
• ABAP and non-ABAP developments (Java, Node.js, and so on.)
• Extension of the UI application with a no-code application such as SAP Build Apps.
• ERP workflow and business process automation.
• Pre/post-processing applications for the SAP S/4HANA system.
• Analytical applications.