For organisations running SAP, the concept of a clean core has become pivotal in ensuring they stay ahead of the curve.
At On Device Solutions, as a specialist SAP partner helping enterprises mobilise and streamline their business processes, we recognise the importance of clean core architecture in realising long-term SAP success – particularly in the transition to SAP S/4HANA and cloud-based landscapes.
In this article, we explore how adopting SAP’s clean core extensibility model can empower businesses to reduce technical debt, accelerate innovation, and optimise system upgrades – all while aligning with On Device Solutions’ implementation and integration best practices.
What is a Clean Core and Why Does It Matter?
A clean core refers to an SAP system landscape that minimises custom code and modifications in the digital core (e.g. S/4HANA), ensuring it remains as close to standard as possible.
This approach allows organisations to:
- Simplify upgrades and patching processes
- Improve overall system performance
- Adopt innovations and cloud services more rapidly
- Lower the total cost of ownership (TCO)
At On Device Solutions, we see this as essential groundwork when advising clients on their SAP S/4HANA migrations or helping them integrate third-party solutions via SAP Business Technology Platform (BTP).
SAP’s Refined Extensibility Model: Four Levels for Cleaner Development
SAP’s latest clean core framework introduces a four-level model (Levels A to D), offering clearer guidance for development teams on how to extend their systems without jeopardising upgrade paths or future cloud readiness.
Level A – The Gold Standard
This level represents the ideal extensibility approach and cleanest form of custom extensions. Extensions are built directly on-stack using ABAP Cloud model or on SAP BTP using tools like SAP Build or SAP’s Cloud Application Programming Model (CAP).
At On Device Solutions, we guide clients toward Level A wherever possible – especially when building custom apps with SAP BTP or extending solutions like SAP Service and Asset Manager.
Level B – The Classic Safe Zone
Level B embraces SAP’s classic extensibility, using nominated BAPIs (Business Application Programming Interfaces) and well-documented objects deemed stable by SAP. While still clean core compliant, it lacks the long-term stability guarantees of Level A and is recommended only if requirements cannot be fulfilled using Level A customisation
This is a practical option for clients still operating within legacy systems but looking to modernise incrementally.
Level C – Conditional Use
Level C includes internal SAP objects that aren’t released or recommended for use but may still be present in legacy custom code. These should be treated with caution and phased out wherever feasible. On Device Solutions can support code reviews and remediation using tools like ABAP Test Cockpit (ATC) to identify such areas.
Level D – Avoid at All Costs
This level covers outdated, unsupported, or high-risk modifications and objects. These directly violate clean core principles and can severely impact system performance and upgradability. Part of our role is helping clients identify and deprecate Level D code through targeted clean-up projects.
Tools to Enable the Clean Core Journey
SAP offers several tools and resources to help organisations assess and improve their core cleanliness:
- SAP Discovery Center – For exploring APIs, extension points, and BTP services
- ABAP Test Cockpit (ATC) – A static code analysis tool used to flag non-compliant custom code
- SAP’s Clarification Repository – For understanding which APIs are supported at each level
- Open-source project “CleanSAPher” – A helpful utility for organisations not on RISE with SAP to measure clean core compliance
At On Device Solutions, we integrate these tools into our assessments and SAP BTP enablement programmes, ensuring clients have a clear view of their system health and roadmap.
A Structured Approach to Extension Planning
SAP’s three-phase methodology for planning extensions consists of:
- Assess the Use Case – Understand the business challenge, context, and requirements.
- Assess the Technology – Determine the most suitable and compliant technical path using available SAP tools and services.
- Define the Target Solution – Create a future-proof, scalable architecture that aligns with clean core principles.
Why Clean Core is More Than Just Good Practice
Keeping your SAP core clean isn’t just about compliance – it’s about building a flexible, future-ready IT landscape that can quickly adapt to changes in the business environment. Whether you’re migrating to SAP S/4HANA, moving to the cloud, or developing mobile-first field service solutions, clean core compliance ensures your efforts don’t become tomorrow’s technical debt.
As SAP continues to evolve its platforms and methodologies, a partner like On Device Solutions can play a critical role in translating best practices into practical, value-driven outcomes. The updated clean core extensibility model provides a much-needed structure for navigating modern SAP landscapes, and we’re here to help our clients make sense of it all.
Whether you’re planning your clean core journey or in the midst of an SAP transformation, we can help you stay aligned with SAP’s future – securely, efficiently, and cleanly.
Contact the team at On Device Solutions now to learn how we can support your SAP transformation with clean core strategy, SAP BTP enablement, and custom mobile solutions.
