Conceptual and architectural design for a cloud-native application for billing and payment. Design, implement, and monitor solutions in SAP BTP with Cloud-Application-Programming Model (Node.js or Java). Build side-by-side and side-core extensions integrating with S/4HANA using APIs and CDS views. Develop REST/OData APIs, manage multitenancy, and implement role-based authentication using XSUAA. Integrate with SAP and non-SAP systems leveraging SAP Event Mesh, SAP Connectivity, and SAP Destination services. Implement microservices with event-driven architecture, messaging queues, and service discovery on BTP Cloud Foundry/Kyma. Configure and consume services like SAP HANA Cloud, SAP Business Application Studio, CI/CD pipelines, and Cloud Transport Management. Plan, design, and develop software systems in accordance with project plans, standards, and processes. Review code to ensure application integration meets internal architectural requirements, functional requirements, system compliance, and interface specifications.