Trying to assign weight and shipping method to an order via the API. It seems that I need to assign a “shipper_id” value to the body content, but I don’t know what the shipper_id corresponds to is or how to retrieve it.
Ultimate goal is to be able to use the API to create orders, then set a shipper and shipping method in order to generate labels (all via the API). I’m trying to do this for a UPS order initially, but will eventually need to do this for FedEx and Endicia as well.
However, that endpoint is (I believe) a V2 endpoint (not identified in the V3 documentation I was told to use). How do I know when to use the V2 documentation (and end points) and when to use the V3 documentation (and end points)?