Modernizing RFC/BAPI-based Integrations for a Clean Core with SAP Integration Suite

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Introduction

In most SAP landscapes, SAP Process Orchestration has long been the trusted bridge between the ERP core and the outside world — connecting SAP and non-SAP systems through RFC & BAPI calls, IDocs, and Web Services, and so on. As organizations now move toward SAP S/4HANA and SAP Integration Suite, the migration journey isn’t just about replacing middleware; it’s about evolving decades of integration logic into cloud-ready, clean-core-compliant patterns.

Among the many interface types found in SAP PI/PO, RFCs/BAPIs stand out as the most functionally embedded. They provide direct access to business objects within the SAP ERP core — for instance, to check material availability, retrieve purchase orders, or update financial postings. This tight coupling, while powerful, also poses modernization challenges, for example by not facilitating easy interoperability with external applications, in today’s composable enterprise era.

Recognizing this, SAP has expanded the Migration Assessment capability in Integration Suite to not only analyze and migrate integration artifacts, but also to recommend modernization opportunities. With the release of Clean Core Modernization Recommendations for BAPIs in Q3 2025, architects can now automatically identify BAPIs used in legacy PI/PO interfaces and discover modern, SAP-managed API equivalents via the SAP Business Accelerator Hub. This opens up a structured path for customers to not just migrate their interfaces, but also modernize them for clean core and interoperability.

Note: In Q2 2025, SAP released Clean Core Modernization Recommendations for IDOCs. Now, this feature is extended to BAPIs as well.

This blog dives into what that means in practice — exploring three architectural paths for evolving BAPI-based integrations as they move from SAP PO to SAP Integration Suite, balancing speed, effort, and alignment with the clean core vision.

A word about “Clean Core” – The Guiding Principle for Continuous Transformation

Clean core is not a product — it’s a philosophy. It is a set of guiding principles that help organizations maintain an agile, upgrade-stable, and innovation-ready ERP landscape. By reducing custom code and relying on standardized, lifecycle-managed APIs and extensions, clean core supports continuous transformation without technical debt. The broader paradigm of Clean core, can be approached in 5 different dimensions, with Integration being one of them, as mentioned in the following figure:

Learn more about the Clean Core approach

Three Architectural Paths to Move BAPI-Based Integrations to SAP Integration Suite

When moving your legacy RFC/BAPI-based interfaces from SAP PO to Integration Suite, there are multiple approaches — each balancing speed, effort, and modernization depth.

Let’s look at these three paths:

Approach	Lift and Shift	Clean Core Modernization	Protocol Modernization
What it entails	Continue to use the RFCs/BAPIs as-is and connect them directly from Integration Suite using the RFC adapter.	Replace BAPIs with standard APIs published by SAP, documented in SAP Business Accelerator Hub.	Replace the RFC connectivity by exposing the same RFC/BAPI as a SOAP Web Service.
Benefits / drawbacks	⇧ Fastest transition with minimal rework ⇧ No revalidation of business logic or functional behaviour ⇩ No interoperability. Opportunity to modernise is not leveraged.	⇧ These APIs are SAP-managed, upgrade-stable, and designed for HANA-optimized data access. ⇧ Facilitates interoperability.	⇩ SOA Manager Z-objects are customer-managed.
Key enablers	Migration Tooling (automated flow conversion from PO ICO to Cloud Integration iflow)	⟹ Migration Assessment → Modernization Recommendations ⟹ Explore APIs on SAP Business Accelerator Hub	Kindly refer following tutorial / blog links: ⟹  How easy it is to consume a Function Module as a Web Service ⟹  Modernize RFC Receiver Connectivity
Best suited for	⟹ Interim phases where backend refactoring is not yet possible (e.g., ECC system, not yet on S/4HANA) ⟹ Projects under strict time constraints where migration speed takes priority	Building a future-ready, interoperable, and clean-core-compliant integration landscape	⟹ Scenarios where no equivalent SAP standard API exists. ⟹ Transitional architectures that need interoperability before full modernization.
Tips & considerations	The best time to start your PO modernization was yesterday — the next best is today. Early planning prevents “lift and shift” compulsions later on.	⟹ Requires functional remapping between legacy BAPI fields and API structure ⟹ Regression testing and business validation needed

Now, we will showcase how a BAPI based interface in our SAP PO landscape can be moved to Integration Suite, applying 1) Lift and Shift, and 2) Clean Core modernization approaches (We will not be covering the Protocol Modernization approach in this post, as it is already nicely covered in the blog / tutorials written by my colleagues – links to which I have shared in the above table).

Example BAPI-based Interface setup in SAP PO:

Consider the example of Material ATP check interface, which uses BAPI_MATERIAL_AVAILABILITY, to fetch the available stock quantity of a given Material, at a given Plant and Storage location. The BAPI is exposed to consuming application SAP CPQ, via a REST API layer, in our SAP PO system. Following are a few screenshots of the interface setup in PO system, specifically also highlighting the request and response fields.

Migration using Lift and Shift approach:

Here, we illustrate how this interface can be moved to Cloud Integration, using Lift and Shift approach, with the aid of Migration Tooling. As we mentioned in the above table, this approach will retain the RFC adapter as it is, in the automatically generated Cloud Integration iflow artifact.

Note: There are additional pre-requisite steps to connect your PO system to BTP sub-account, through the Cloud connector. Kindly refer this help portal page, for more details. This is an essential step, to be able to do Migration Assessment as well as to migrate interfaces from PO to Cloud Integration, using Migration Tooling.

We launch the Migration Tooling guided wizard, by clicking the Migrate button, from within the package.

At the end of the guided wizard, we see that the integration flow is automatically generated, keeping the technical implementation aspects, exactly as it was in PO system (such as connectivity protocols, message mappings, message schema, etc.)

The iflow is broken into multiple integration processes, for better readability. In this case, the request and response mapping steps are modularised into separate integration processes, which are called from the main integration process.

The following screenshot shows a closer view of the main integration process – with receiver adapter RFC being used to call S/4HANA system, to fetch the Material ATP information.

Migration using Clean Core Modernization approach:

Next, we will walk you through the Clean core modernization approach, to move our BAPI_MATERIAL_AVAILABILITY based interface to Cloud Integration.

As stated in the beginning of this post, we start with analysing the latest generated Migration Assessment report. If you have run the migration assessment of your PO landscape before SAP released the “Clean Core Modernization Recommendations for BAPIs” feature, kindly re-run the assessment. The new version of the report will have additional worksheets, containing these recommendations.

In the Recommendations sheet, you can see the Possible Modernization Item across each pillar – such as Protocol, Security, Clean core, Integration Style, etc.

In the API Recommendations sheet, you can see the equivalent S/4HANA API for the underlying BAPIs used in each of the PO interfaces, that uses BAPI based integration.

Next, we proceed to Business Accelerator hub, to explore the API definition of the recommended API:

This OData API can be adopted in our Cloud Integration iflow or be exposed to other applications via API Management layer, to fetch the Material ATP details. We leave the implementation details to you, to model the orchestration layer, as you deem fit, based on your business scenario.

With this approach, we have modernized a BAPI based integration into a modern one – i.e. OData API based, thereby reaping the benefits such as upgrade-stable interface, clean core, interoperability, and so on.

Closing Thoughts

Integration modernization is not just a migration exercise — it’s an opportunity to realign enterprise integration with the clean core vision and build a foundation for continuous transformation & business agility, by taking advantage of the modern, cloud-native features and open protocols offered by SAP Integration Suite.
Every interface we modernize is a building block of a cleaner, more interoperable ERP core. With SAP Integration Suite and the new modernization recommendations, the journey from legacy BAPIs to standard APIs has never been clearer — or more achievable.

Related Reading: If you’re working on IDoc-based integrations, check out my earlier post on how to modernize IDoc to APIs and Events, leveraging the Migration Assessment modernization recommendations for IDOCs.