Explanation Make a callout to the payment gateway through ESB supporting error handling and logging for audit purposes. This solution meets the requirements of integrating with an external RESTful service, ensuring real-time updates to the CSR, and supporting post payment processes. ESB stands for Enterprise Service Bus, which is a software architecture model that allows communication between different applications via a common bus. ESB can handle the callout to the payment gateway service, and provide error handling, logging, routing, transformation, and orchestration capabilities. ESB can also integrate with other systems or services that are involved in the post payment processes, such as billing, invoicing, or reporting. References: Certification - Integration Architect - Trailhead, [Enterprise Integration Patterns]
