SAP BTP Integration Interview Questions

An IDoc is an Intermediate Document used in SAP to exchange business data asynchronously between systems. First, I would explain that an IDoc is not the business document itself, but a technical container that carries structured information for integration. It contains a control record, data records and status records, which together identify the message, hold the payload and track processing. This makes it suitable for master data and transactional integrations where decoupled communication is needed. A strong candidate would add that IDocs help standardise external and internal interfaces and allow processing to be monitored and retried.

I check coupling and timing. If logic must run inside an SAP transaction, such as blocking save, a released in-app BAdI or developer extensibility option may be better. If the requirement is loosely coupled, external-data-driven, analytical, workflow-oriented or independently lifecycle-managed, side-by-side extension on BTP may be better.

A BAPI is a Business Application Programming Interface. It is a released SAP function module used to perform standard business operations such as creating sales orders, posting goods movements or creating materials without directly updating SAP standard tables. BAPIs help ensure SAP standard validations, update logic and business consistency are followed.

The Cloud Foundry (CF) runtime is a mature, polyglot environment that uses buildpacks to manage application lifecycles, making it the go-to choice for standard business logic and CAP-based applications where the developer wants to focus on code rather than infrastructure. In contrast, the Kyma runtime is based on Kubernetes and is designed for containerized microservices and event-driven architectures using Docker and Helm. You should choose Cloud Foundry for rapid development of standard web applications and extensions where standard buildpacks suffice. Kyma is preferred when you need full control over the container orchestration, require sidecar patterns, or need to handle high-volume event processing from SAP S/4HANA using its native integration with the SAP Event Mesh.

To connect BTP applications to an on-premise S/4HANA system, we use the SAP Cloud Connector in conjunction with BTP Destinations. The Cloud Connector is a small agent installed behind the customer's firewall that initiates an outbound SSL tunnel to BTP, meaning no inbound ports need to be opened, which satisfies high-security requirements. Inside the Cloud Connector, we define which specific on-premise resources (like OData services or RFCs) are exposed. On the BTP side, we create a 'Destination' which stores the connection URL (often a virtual host defined in the Cloud Connector), the proxy type (On-Premise), and the authentication credentials. When a BTP app calls the destination, the request is securely routed through the tunnel to the specific on-premise S/4HANA system.

SAP Integration Suite is an integration platform-as-a-service (iPaaS) that allows for seamless connectivity between SAP and non-SAP systems, whether they are in the cloud or on-premise. Its core component, Cloud Integration (formerly CPI), uses Integration Flows (iFlows) to define the path and transformation logic for data. A typical iFlow use case would be integrating SAP SuccessFactors with an on-premise Payroll system: the iFlow would start with a timer or HTTPS sender, fetch changed employee records using the SuccessFactors adapter, transform the data format (e.g., JSON to XML) using a mapping step, and finally send the data to the on-premise system via the SAP Cloud Connector using the IDOC or SOAP adapter. This ensures data consistency across the landscape without direct point-to-point connections.