Some carriers have several different return products while others don't have any. Customers have different agreements with carriers so nShift doesn't know which product is the correct one for you. Ask your carrier if you have doubts.

Creating a return shipment using our Shipment Server API is very much like creating a standard shipment. You have to include the correct ProdConceptID of your return product in the request and switch the sender and receiver addresses. The API knows from the ProdConceptID if it is a standard or a return product. You can switch the addresses by switching the Kind value from the standard shipment.
 

A return shipment is always made in a separate request. It is not possible to make a return shipment automatically together with a standard shipment.

Example of the addresses on a standard and a return shipment:

Standard shipment:

 "Addresses": [
        {
            "Kind": 2,
            "Name1": "Test sender",
            "Street1": "Test Address",
            "PostCode": "0580",
            "City": "OSLO",
            "Phone": "23249480",
            "Mobile": "04799999999",
            "Attention": "test",
            "CountryCode": "NO"
        },
        {
            "Kind": 1,
            "Name1": "John Doe",
            "Street1": "Test address 1",
            "Street2": "Test address 2",
            "PostCode": "0580",
            "City": "OSLO",
            "CountryCode": "NO"
        }
    ],

Return shipment (kind 1 and 2 have simply been switched)

 "Addresses": [
        {
            "Kind": 1,
            "Name1": "Test sender",
            "Street1": "Test Address",
            "PostCode": "0580",
            "City": "OSLO",
            "Phone": "23249480",
            "Mobile": "04799999999",
            "Attention": "test",
            "CountryCode": "NO"
        },
        {
            "Kind": 2,
            "Name1": "John Doe",
            "Street1": "Test address 1",
            "Street2": "Test address 2",
            "PostCode": "0580",
            "City": "OSLO",
            "CountryCode": "NO"
        }
    ],

The Kind value is what defines the address type where 1 is the sender and 2 is the receiver. See our appendix here.