Side-by-Side Extensions
Side-by-side extensibility is the architectural pattern of building custom logic, UIs, and integrations on a platform outside the SAP S/4HANA digital core (typically SAP BTP) rather than modifying the core system directly. This topic covers when to choose side-by-side over in-app or classic extensions, how these extensions connect to the core, the governance and NFR trade-offs involved, and how they support a clean-core strategy across ECC-to-S/4HANA transitions and hybrid landscapes.
Overview
Side-by-side extensibility is the architectural pattern of building custom logic, UIs, and integrations on a platform outside the SAP S/4HANA digital core (typically SAP BTP) rather than modifying the core system directly. This topic covers when to choose side-by-side over in-app or classic extensions, how these extensions connect to the core, the governance and NFR trade-offs involved, and how they support a clean-core strategy across ECC-to-S/4HANA transitions and hybrid landscapes.
Lessons in this topic
- SAP Side-by-Side Extensions Tutorial (Part 1)Introduces the business and technical rationale for side-by-side extensions, contrasting them with in-app and classic ABAP extensions, and explains the core decision criteria for choosing this pattern.
- Integration Patterns and Runtime Flow for Side-by-Side Extensions (Part 2)Explains how side-by-side extensions built on BTP communicate with the S/4HANA core at runtime, covering synchronous and asynchronous integration patterns, authentication, and typical failure points.
- Integration Patterns and Data Synchronization for Side-by-Side Extensions (Part 3)Explains how side-by-side extensions communicate with SAP core systems, covering integration styles, data consistency approaches, latency trade-offs, and error handling patterns needed for reliable production operation.
Interview questions covered
- What are the core concepts of Side-by-Side Extensions, and how would you explain them clearly in an SAP interview?
- How would you apply Side-by-Side Extensions in a real SAP project? Walk through the design or implementation approach.
- A production issue is reported in Side-by-Side Extensions. 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 Side-by-Side Extensions?
- Suppose you inherit an existing Side-by-Side Extensions solution. How would you review it before making a change?
- A project encounters this situation while working on Integration Patterns and Runtime Flow for Side-by-Side Extensions: A logistics company's side-by-side extension on BTP subscribes to goods-issue events from an S/4HANA private cloud system to trigger a customs documentation workflow. 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 Integration Patterns and Data Synchronization for Side-by-Side Extensions: A retail customer built a side-by-side credit-risk scoring application on SAP BTP that needed near-real-time visibility of sales order values against customer credit exposure. Walk through how you would analyze the requirement or issue, what you would validate, and how you would test the solution before release.
- Using this SAP project situation — A retail company migrating from ECC to S/4HANA Cloud public edition needs a custom promotions engine that calls out to a third-party pricing API and applies complex discount rules not supported by standard condition technique — explain Why Side-by-Side Extensibility Exists and When to Use It. What should happen, which concepts or process steps matter, and what common mistake would you avoid?