API Request - Epicor (ERP) and Ecwid (E-Commerce)

I need an API request developed for Epicor (ERP) and Ecwid (E-Commerce). The data that needs to be transferred between the two systems is sales orders, so that the right information appears in both applications. I have specified that data should be synced via scheduled data sync. Epicor will act as the primary source of data; any information present in the system will need to be replicated in Ecwid. The API integrated must ensure both foundational and security requirements are met, so that data is synchronization accurately and securely. API documentation is available from both companies.