Create a label for an existing shipment and retrieve it synchronously.

Required authorization scope: public.label:write

This API finalizes a shipment created via the Shipment API. Executing this call will book the shipment with the selected courier, trigger label generation, and prepare all necessary shipping documents—provided your account balance is sufficient.

You can enter a courier_service_id to assign a specific courier service in case your shipment has no assigned courier yet, or you need to overwrite the one suggested by default. Your shipment will be confirmed. If there is no assigned courier service and you leave the courier_service_id field blank, we will automatically assign the best value for money courier to your shipment.

This API is in beta (subject to change).