One of the biggest challenges companies face when implementing SAP S/4HANA is how to adapt the system to real-world business processes without compromising scalability, maintainability, or future upgrades.
This is especially true in industries like energy, manufacturing or logistics, where custom workflows, sector-specific logic and complex integrations are the norm.
The answer is not to return to the “Z-development” mindset of the past. The real solution lies in designing an architecture that extends SAP without touching the core.
Why Standard SAP Doesn’t Always Fit
SAP S/4HANA offers a strong standard framework, but:
- Every company has unique needs: invoicing structures, pricing formulas, validation flows, approval hierarchies
- Industry-specific or regulatory requirements often add layers of logic
- Legacy systems and third-party tools require tight, often custom integration
The problem isn’t SAP. The problem is how companies adapt it.
The Wrong Approach: Customizing the Core
Historically, the easy answer was to build custom code directly in SAP:
- Z-developments for new logic
- Hard-coded enhancements inside standard modules
- Direct integration points without abstraction
- Upgrade-Probleme und technisches Risiko
- Acoplamiento excesivo entre procesos y tecnología
This leads to:
- High maintenance costs
- Upgrade issues and broken compatibility
- Hidden business logic with no audit trail
- System dependencies that make scalability nearly impossible
In the S/4HANA era — especially in cloud or RISE models — this approach no longer works.
Yes, You Can Adapt SAP Without Breaking the Core
The key is to adopt a modular, extensible architecture that separates business logic from the core system — using the tools SAP provides for precisely this purpose.
Let’s look at the most effective options.
4 Smart Ways to Extend SAP Cleanly
- SAP Business Rules
External, version-controlled rule management. Business users can maintain logic without coding, ideal for pricing, validations, workflows or exceptions that change often. - Side-by-Side Extensions via SAP BTP
Independent services and apps that connect to SAP via APIs and events. Perfect for complex workflows that require flexibility but must stay aligned with SAP processes. - SAP Event Mesh
Trigger real-time events from SAP processes (“invoice created”, “customer updated”) to activate external logic, notify systems or enforce additional compliance rules. - SAP Integration Suite + APIs
Enable secure, scalable and monitored integration with legacy systems or external services — without custom coding inside SAP.
Real-World Example: Complex Invoicing in the Energy Sector
An energy company needs to calculate customer-specific charges based on:
- Contract terms
- Usage type
- Time of year
- Regional regulations
❌ Traditional approach:
- Custom Z-code in IS-U
- Complex formulas buried in ABAP
- Every change needs development and testing
✅ Modern approach:
- Calculation logic in SAP Business Rules
- Invoice event triggers calculation service
- External logic returns pricing
- All steps are traceable, versioned and auditable
How We Do It at principal33
At principal33, we support companies across regulated and complex industries to modernize SAP without losing control.
Our methodology:
- Audit existing custom logic
- Propose a clean core extension architecture
- Separate logic, data, and workflows
- Use SAP BTP, Business Rules and Event Mesh
- Enable both IT and business users to manage processes efficiently
The result: an SAP system that reflects real business complexity without sacrificing maintainability or agility.
Conclusion: Customization Doesn’t Have to Break SAP
Companies don’t have to choose between rigid standards and risky customization.
With the right strategy, SAP can support complex, evolving processes without breaking the core.
In 2026, this approach will define which organizations thrive — and which are stuck maintaining yesterday’s code.
