I've been digging through and testing the FulfillmentOrder and this doesn't seem possible so I want to verify. We have a lot of merchants asking us to set the fulfillment location when an order is created. Shopify has supported multiple locations for a long time and it would make sense for developers to be able to set the location of the fulfillment on order creation. We have a lot of merchants who user our apps that need to set different locations when doing an import.
If I have this correct, it seems there is only one way to set the fulfillment location and that is by first creating the order, then pulling the orders FulfillmentOrders and finally making a call to move the FulfillmentOrder to the new location. There are a few issues I can see with this:
A simple solution here would be to support adding a FulfillmentOrder when sending Order data to the Order API. This is how the majority of other associated resources work when creating orders so it makes sense that the FulfillmentOrder would be the same. This will keep the API consistent and efficient, it also cuts down on unnecessary API calls.
So my two questions are:
As always, thanks for the help and time looking over my question!