Using Salesforce custom object, custom REST API and ETL is a better solution than using Salesforce standard object, REST API and ETL. A custom object can store the order information and provide more flexibility and control overthe data model, validation rules, triggers, etc. A custom REST API can be used to create orders in real time from Salesforce, using the ESB as a proxy to communicate with the legacy system. An ETL tool can be used to sync the order history and status fromthe legacy system to Salesforce, using the last modified date as a filter. This way, sales reps can see the order history and the most up-to-date information on current order status, and managers can run reports on order volumes and fulfillment timelines. A standard object, such as Order, may not meet all the business requirements and may require more customization than a custom object. A standard REST API may not provide enough security and error handling for creating orders in real time. Reference: Salesforce Integration Architecture Designer Resource Guide, page 18