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# [Trends] Composable Supply Chain and the "Clean Core" Concept
- URL: https://www.s4journal.com/composable-supply-chain-and-the-clean-core-concept/
- Published: 2026-09-19T21:52:30.000Z
- Updated: 2026-09-19T21:53:29.000Z
- Author: Kamil Szcześniak
- Tags: Supply chain

Traditional Warehouse Management Systems (WMS) and ERPs were built as monolithic structures where source code was modified directly to fit business needs. The "Composable" approach is a complete departure from this model, favoring an ecosystem of independent microservices based on MACH architecture (Microservices, API-first, Cloud-native, Headless).

### What is the "Clean Core"?

In the context of SAP S/4HANA (and other modern ERPs), the *Clean Core* principle means a strict prohibition on modifying the standard source code (i.e., avoiding traditional "Z-enhancements" in ABAP directly within the transactional system).

The system's core must remain 100% standard to allow the organization to seamlessly apply quarterly cloud updates and upgrades without extensive regression testing.

### How is Custom Logic Handled in a Composable Architecture?

All non-standard, custom business logic is moved outside the core system using a concept called *Side-by-Side Extensibility*.

**Real-world Examples & Implementation:**

- **External Cartonization Algorithm:** Imagine an e-commerce company shipping irregularly shaped products. The standard packing mechanisms in SAP EWM struggle to optimize space. Instead of writing thousands of lines of custom ABAP code, the company integrates an advanced external service (e.g., Paccurate) via API. SAP EWM simply sends the product dimensions, and the external service returns the optimal 3D packing pattern in milliseconds. This logic runs entirely outside of S/4HANA (e.g., on SAP BTP), leaving the core untouched.
- **Dynamic Rate Shopping:** During delivery creation, the system needs to select the most cost-effective carrier, factoring in real-time fuel surcharges and zone rates. A monolithic system would require constant, heavy table updates. In a composable architecture, S/4HANA merely triggers an Event indicating a package is ready. An external microservice then queries carrier APIs (like FedEx, UPS, or DHL) and pushes the final shipping label and exact cost back to the ERP.

**Case Study:** **PUMA** implemented a composable architecture (using Manhattan Active solutions), completely eliminating traditional system upgrade cycles. They moved to a Continuous Integration/Continuous Deployment (CI/CD) model, where updates and new features are pushed seamlessly without ever disrupting warehouse operations.