Understanding the difference between reference_no and uid is essential for proper integration.

reference_no: The reference_no identifies the current object in the source system. E.g. the booking reference_no identifies the booking in the DC System and the shipment reference_no identifies the shipment in the forwarder system.

uid: The uid is generated in the Setlog Forwarder API to make the current object unique overall customers and forwarders. It is based on the reference_no and included the customer prefix like e.g. 'DC-' for this integration. Therefore uids from booking needs to be sent back in the shipment message if required. Please see more details below.