SAP S/4HANA is SAP’s latest ERP system that runs on the fast, in-memory SAP HANA database. It’s a major shift from the traditional SAP ECC system—not just technically, but also in how businesses operate. For developers entering this world, there are some important things to understand upfront. Whether you’re transitioning from ECC or coming in fresh, here’s what you need to know before working with S/4HANA. Accely SAP S/4HANA solutions offer expert guidance to help businesses and developers navigate this transition more effectively.
1. Understand What S/4HANA Is
First things first—S/4HANA isn’t just a faster version of ECC. It’s a complete redesign. This results in significant performance gains, as well as changes in how data is modeled and accessed.
The “S” stands for “Simple,” and much of that simplicity stems from a streamlined data model. Tables have been reduced, many traditional aggregates and indexes are gone, and transactions have been restructured. If you’re used to custom code based on the old table structures, you’ll need to rework it.
2. You’ll Need to Learn ABAP—But Modern ABAP
Yes, ABAP is still around. But it’s evolved. Modern ABAP in S/4HANA supports new syntaxes, inline declarations, and cleaner code structures. You’ll also work with concepts like ABAP Core Data Services (CDS), which are a new way of defining and consuming data models directly at the database layer.
CDS views are now central to reporting and data access in S/4HANA. They’re declarative, can include annotations for UI and analytics, and often replace older custom reports and ALV grids. Learning how to create and extend them is essential.
3. Fiori Is the User Experience Standard
Forget SAP GUI as the main interface. While it’s still available, SAP is pushing hard for Fiori—a modern, web-based UI built on SAPUI5 and OData. Fiori apps are role-based, responsive, and simpler for users.
As a developer, this means learning front-end skills (like JavaScript and XML views), along with the OData protocol to expose backend data to the Fiori apps. Even if you’re focused on backend development, understanding how your work ties into Fiori is key.
4. Custom Code Needs Review and Refactoring
If you’re working on a system migrating from ECC, expect to spend time analyzing existing custom code. A lot of it won’t work as-is in S/4HANA. You’ll need to check for:
- Deprecated transactions and function modules
- Direct table reads from tables that no longer exist
- Poor performance due to outdated logic
SAP offers tools such as the Custom Code Migration app and ABAP Test Cockpit to assist with this. It’s not glamorous work, but it’s critical to a successful S/4HANA implementation.
5. SAP HANA Brings a Shift in Mindset
In traditional ABAP, you’d often load lots of data into memory and then process it in loops. With HANA, the idea is to push logic down to the database layer. You want to minimize data transfers and let the database do the heavy lifting.
This approach is often referred to as “code pushdown,” which involves utilizing CDS views, AMDP (ABAP Managed Database Procedures), and SQLScript more effectively. It’s a change in habits, but one that pays off in performance.
6. Extensions Should Be Built the Right Way
SAP encourages a “clean core” approach with S/4HANA. That means not modifying standard SAP code. Instead, use extension frameworks like:
- In-app extensions – using the key-user tools inside Fiori
- Side-by-side extensions – building new functionality on SAP Business Technology Platform (BTP)
This keeps your system upgrade safe and aligned with SAP’s roadmap. For developers, this often means learning new tools, such as SAP BTP, CAP (Cloud Application Programming Model), and REST APIs.
7. Testing and Quality Control Are More Important Than Ever
With so much changing under the hood, testing can’t be an afterthought. Automated testing—specifically, unit tests, integration tests, and regression tests—should be integrated into your development cycle. SAP provides tools like ABAP Unit and integration with CI/CD pipelines to support this.
And since performance is often a top priority with S/4HANA, it’s smart to get familiar with tools like the SQL Performance Tuning Worklist and ABAP Runtime Analysis early on.
8. Be Ready to Collaborate Across Teams
S/4HANA projects aren’t just about code. They involve business process redesign, user training, data migration, and other related activities. Developers are expected to work closely with functional consultants, architects, and users. It helps to be curious, not just about how the system works, but why things are done a certain way.
If you’re used to working in a silo, this can feel like a big shift. However, it also means you’ll have a greater impact and learn more about how businesses operate.
Final Thoughts
S/4HANA presents numerous opportunities for developers, but also a significant learning curve. It’s not just about picking up some new syntax or tools. It’s about rethinking how applications are built, how data is handled, and how your work aligns with the broader business goals.
If you’re open to learning and willing to adapt, working with S/4HANA can be a rewarding step in your development career. But go in with your eyes open, take the time to understand the platform’s foundations, and be ready to unlearn some old habits along the way.