Clean Core
Clean Core is the architectural discipline of keeping the S/4HANA digital core upgrade-safe by minimizing modifications and classic customizations, and instead extending SAP functionality through released APIs, in-app extensibility tools, and side-by-side platforms such as BTP. This topic covers why Clean Core matters for upgradeability and TCO, the extensibility options and their trade-offs, governance mechanisms to enforce clean core over time, and how these decisions differ across ECC, S/4HANA on-premise/private cloud, and public cloud.
Overview
Clean Core is the architectural discipline of keeping the S/4HANA digital core upgrade-safe by minimizing modifications and classic customizations, and instead extending SAP functionality through released APIs, in-app extensibility tools, and side-by-side platforms such as BTP. This topic covers why Clean Core matters for upgradeability and TCO, the extensibility options and their trade-offs, governance mechanisms to enforce clean core over time, and how these decisions differ across ECC, S/4HANA on-premise/private cloud, and public cloud.
Lessons in this topic
- SAP Clean Core Tutorial (Part 1)Introduces the clean core concept, why SAP and customers adopted it, and the core problems it solves compared to classic ECC customization practices.
- Extensibility Models and Trade-offs Under Clean Core (Part 2)Explores in-app, developer, and side-by-side extensibility options under clean core, with concrete trade-offs for choosing between them across deployment models.
- Choosing Extension Patterns: In-App vs Side-by-Side under Clean Core (Part 3)How to decide between in-app key-user extensibility, developer extensibility, and side-by-side extensions on BTP, and how that choice affects integration flow and long-term maintainability.
- Clean Core Governance, Operations, and Long-Term Roadmap Management (Part 4)Establishes the governance structures, monitoring practices, and roadmap planning needed to sustain a clean core over multiple release cycles, including how to measure extensibility health and manage cost trade-offs.
- Data Boundaries, Security, and Governance for Clean Core Extensions (Part 5)How to enforce API-only data access, design the security model for extensions, and establish governance controls that keep custom code upgrade-safe over time.
Interview questions covered
- What are the core concepts of Clean Core, and how would you explain them clearly in an SAP interview?
- How would you apply Clean Core in a real SAP project? Walk through the design or implementation approach.
- A production issue is reported in Clean Core. What would you check first, and how would you troubleshoot it systematically?
- What are the most important design decisions, trade-offs, and best practices in Clean Core?
- Suppose you inherit an existing Clean Core solution. How would you review it before making a change?
- Using this SAP project situation — A retail customer migrating from ECC 6 — explain Why Clean Core Matters: Business and Technical Rationale. What should happen, which concepts or process steps matter, and what common mistake would you avoid?
- Using this SAP project situation — A retail company completed its S/4HANA private cloud clean core migration eighteen months ago — explain Clean Core Governance, Operations, and Long-Term Roadmap Management. What should happen, which concepts or process steps matter, and what common mistake would you avoid?
- A project encounters this situation while working on Extensibility Models and Trade-offs Under Clean Core: A manufacturing company running S/4HANA Private Cloud needed a custom rebate calculation that varied by regional sales organization. Walk through how you would analyze the requirement or issue, what you would validate, and how you would test the solution before release.
- A project encounters this situation while working on Choosing Extension Patterns: In-App vs Side-by-Side under Clean Core: During an S/4HANA private cloud migration, a retail customer needed a custom loyalty discount calculation. Walk through how you would analyze the requirement or issue, what you would validate, and how you would test the solution before release.
- You are the senior consultant/architect responsible for Data Boundaries, Security, and Governance for Clean Core Extensions. The project situation is: An architecture review during a private cloud rollout discovered that a side-by-side BTP extension had been using a technical service account with broad authorizations to call an internal, unreleased API endpoint because the released equivalent lacked one required field. How would you assess the design, identify the highest-risk failure modes, and define the evidence required before approving it for production?