If you're using ShipStation's API to ship orders or pull shipping information, it's important that your API requests use the 'carrierCode' and 'serviceCode' values that are mapped to the ones in ShipStation's user interface.
When building an API connection for a specific ShipStation account, use the 'List Carriers' and 'List Services' endpoints to get the 'carrierCode' and 'serviceCode' values that matter for the account you're working with. For more details on those endpoints, please refer to our API documentation.
For those of you building a connection that requires you know all possible values for 'carrierCode' and 'serviceCode', please refer to the Excel file at the bottom of this article. It has every API value for the active providers/carriers currently available in ShipStation. Since shipments also require a specified 'confirmation' type, the Excel file also contains a breakdown of possible confirmation types for each provider/carrier.