The Side-by-Side Extension in SAP BTP You May Not Be Already Using

Introduction

If you work with SAP today, particularly in the realm of SAP S/4HANA, SAP ECC or our cloud products, it’s likely that you may have heard of the guiding principle known as “Keep the Core Clean.”

But here’s the real question:
Are you really working with the side-by-side extension concept on SAP BTP to make that achievable?

Classic in-system customizing (Z-tables, enhancements, modifications) is still widely used by organizations and represents a technical debt that makes upgrades more difficult. Side-by-side extensions on SAP BTP provides a modern complement to that: you develop and run your custom code outside of the core system, but in a way that closely integrates with it.

If you haven’t already tapped side-by-side extensions, you could be sleeping on one of the most powerful SAP BTP capabilities you’re already paying for—but have yet to leverage.

What’s a Side by Side Extension in SAP BTP?

In simple terms:
A side-by-side extension is a bespoke app or service solution, built on SAP BTP, that extends your SAP system but does not alter its core.

Rather than changing SAP S/4HANA or SAP ECC directly, you:

• Expose core system APIs, events or OData services
  
• Develop custom apps, processes or services on SAP BTP
  
• Bring them back to SAP using secure, managed connections
  

This allows you to innovate fast and keep your SAP core as stable, upgradable and clean as possible.

Key Characteristics

• Operates on SAP BTP, not directly in the core system
  
• Leverage standard APIs, events and integration approaches
  

Built using:

• SAP CAP(Cloud Application Programming Model)
  
• SAP Build Apps (low-code)
  
• SAP UI5 / Fiori
  
• Node.js / Java services
  

Connects via:

• SAP Cloud Connector
  
• SAP Integration Suite
  
• Destination service and OAuth
  

Why Side-by-Side Extension Matters More Than Ever

Keep the Core Clean

With RISE with SAP, S/4HANA Cloud and regular upgrades, in-core tuning bricks up businesses. Side-by-side extensions:

• Avoid core code modifications
  
• Reduce regression risk during upgrades
  
• Fit nicely into SAP’s pure core strategy
  

Faster Innovation Cycles

Need to:

• Launch a new customer portal?
  
• Have a new logistics carrier come on?
  
• Add AI-based recommendations?
  

Running that in the Mailpile core can be slow and complicated. On SAP BTP, you can:

• Develop faster with modern tools
  
• Deploy independent of ERP downtime
  
• Test, iterate and scale without changing production core code.
  

Scalable, Cloud-Ready Architecture

As your business expands so does:

• User volumes
  
• Data loads
  
• Integration complexity
  

Side-by-side extensions operate in a cloud-native environment on BTP—allowing you to scale services when needed without burdening your core ERP.

What are the Key Features and Benefits of Side-by-Side Extensions in SAP BTP?

• Customization: Create bespoke custom applications and microservices to mold complex business processes.
  
• Scalability: Leverage BTP’s elastic, multi-region infrastructure.
  
• Security: Identity Authentication, collection of roles and secure communication.
  
• Futureproofing: Prevent new ideas from becoming trapped in overly tailored solutions.
  
• Vendor Alignment: Compliant with SAP’s extension strategy.
  

A Precise Case: Side-by-Side Use Scenario side by side

Let’s go through a practical, real-world, compound example that (sort of) mirrors what a lot of companies are doing now.

Company Background

A global wholesale distributor runs:

• SAP S/4HANA as its core ERP
  
• Multiple third-party logistics (3PL) partners
  
• An old customer portal that is difficult to upkeep
  

They want:

• A new partner, customer portal
  
• Instant information on orders, deliveries and invoices
  
• A method of rapidly incorporating a new logistics provider
  
• Modest disturbance to their SAP S/4HANA system
  

Challenge

Previously, every new requirement meant:

• Enhancements in the core
  
• Existing SAP Fiori apps now can be modified
  
• Risk during upgrades
  
• BAPI, ABAP, and functional also involved in long development cycles
  

They wanted a way to innovate at the edge, while maintaining stability in the core.

Solution: 

Side-by-Side Extension on SAP Business Technology Platform

The company is partnering with Cremencing Solutions to architect a side-by-side:

Expose SAP Data Securely

• Leverage OData APIs and CDS views available in S/4HANA
  
• Set up SAP Cloud Connector to connect on-prem (or private cloud) ERP with SAP BTP
  
• Secure access via Destionations in BTP
  

Create the Extension App on SAP BTP

On SAP BTP, they develop:

A CAP-based backend service to:

• Consolidation of data from SAP and 3PL systems
  
• Apply custom business logic
  
• Take control of individual shopper views by order or delivery
  

A frontend in SAPUI5/Fiori or otherwise and an SAP Build Apps front-end for:

• For a customers to just be able to log in and see orders
  
• Logistics partners to confirm shipments
  
• Internal teams to track exceptions
  

Integrate 3rd Party Logistics Providers

Using SAP Integration Suite, they:

• Use APIs of various 3PLs
  
• Normalize shipment status data
  
• Send updates or status reports back into S/4HANA when necessary
  

Outcome

After implementing the side-by-side extension:

• Real-time tracking of orders and deliveries for customers
  
• A single, modern UI for business users without complex SAP GUI/Fiori modifications
  
• IT reduces core modifications dramatically
  
• New logistics service providers can be added without impacting S/4HANA
  

Business Impact:

1.) Less “Where is my order?” support tickets
Faster onboarding of new partners
Less SAP core and smoother incentives Some insights:LOWER investments in SAP code which means SMOOTHER upgrade paths.

This is the one type of, side-by-side extension in SAP BTP that many businesses might be utilizing — just haven’t consumed yet.

Side-by-Side vs In-App Extensions - When to Use Each?

There isn’t a one-size-fits-all approach. Both have their place:

In-App Extensions (Key-User / Developer Extensibility) Use When:

• You’re making simple UI adaptations
  
• You’re adding a custom field to standard apps
  
• You’ll get localised logic in S/4HANA only
  

Use Side-by-Side Extensions When:

• You are creating new applications, or portals
  
• You need cross-system integrations
  
• You require independent scalability
  
• You wish to use AI, events, workflows and low-code capabilities on BTP
  

In most contemporary landscapes, you’re going to get a hybrid model: basic modifications in-app; complex upgrades side-by-side.

Technical Sidewalks For The Side By Side Extensions

When you develop a side-by-side extension on SAP BTP, most of the time you would be using:

• SAP BTP, Cloud Foundry-Runtime bzw. Kyma
  
• Cloud or any other supported data stores
  
• CAP-based services (Node. js/Java)
  
• SAP Fiori/UI5 or SAP Build Apps UIs
  

SAP Event Mesh is a wiring fabric for event-driven architectures

Advantages of Side-by-Side Extensions 

• Designed for scale and performance
  
• Agile Computing Agility: Faster development and deployment cycles.
  
• Composable: Microservices and modular services
  
• Strategic: In total harmony with the future roadmap of SAP
  

Helping You Effectively Utilize Side-by-Side Extensions

As an SAP Custom Development and SAP BTP partner, we usually help customers with:

• Architecture Design: Side-by-side vs in-app, integration patterns, security model
  
• Proof of Concept (PoC): Take baby steps in one realt person scenario
  
• End-to-End: Full implementation from networking to UI and deployment
  
• Coaching & Enablement: Helping your internal team with BTP development techniques
  
• Lifecycle Support – Ongoing monitoring, tuning, and improvement
  

If you’re not currently using the side-by-side extension pattern, we can work together to identify quick-win use cases, and to create your first production-ready solution.

Conclusion

The side-by-side extension is more than a technical possibility in the SAP BTP – It’s a benefit which reflects that your business is able to:

• Innovate faster
  
• Keep the SAP core clean
  
• Integrate more systems
  
• Deliver modern user experiences
  
• Continue to be aligned with the long term vision of what SAP is doing
  

If you are still primarily using conventional ABAP modifications and in-core customizing, the time to reconsider is now. For more insights on SAP BTP check out our detailed blog on Understanding SAP BTP Basis and Modules: What They Do and Why They Matter to deepen your understanding.

Now, you may already have SAP BTP, but what if the side-by-side extension you’re not leveraging yet is the catalyst for your next wave of digital transformation?

FAQs 

What is the side-by-side extension on SAP BTP?

A side-by-side extension is an explicit custom application or service executed on SAP BTP to extend some behavior of your SAP system without touching its core. It has got APIs, events and integration points to not get locked down so you can innovate while keeping the core clean.

Why would I use side by side extension over classic customization?

Side-by-side extensions:

• Avoid risky core modifications
  
• Support easier upgrades
  
• Allow cloud-native, scalable development
  
• Faster innovation and integration with other systems on what they excell at.
  

They are aligned with SAP’s clean core and RISE with SAP strategy.

Are all in-app extensions replaced by side-by-side extensions?

No. In-app (key-user) extensions are still useful for minor changes like new fields or adapting UIs. “Side by side Extensions are great for new applications, cross-system processes, and complex logic that should not reside in the ERP core.

How long does a side by side extension take to build?

Typical timelines:

• Simple PoC: 2–4 weeks
  
• Medium-complex app: 6–10 weeks
  
• Feature-rich enterprise solution with several integrations: Several months, range varies base on features
  

Resources

Official SAP Resources

• SAP Business Technology Platform Overview
  https://www.sap.com/products/business-technology-platform.html
  
• SAP Extensibility Explorer and Clean Core Guidance
  
• SAP Help Portal - SAP BTP & Extension Suite
  
• SAP Community: BTP extensions blogs and q&a articles