Getting Started with Orders
ShipEngine allows you to integrate with many order sources, and more integrations are being added all the time. It’s important to note that ShipEngine is not just any other “Orders API”; we’re designed around handling everything from a simple online order source to enterprise ERP solutions. This is why we’ve introduced the Sales Order API.
Differences between Sales Orders and Orders
The idea of a sales order is much broader, it encompasses the topmost level of an order. A sales order will encompass all of the facets of your order.
The "Sales Order" and "Sales Order Item" are to be immutable by ShipEngine and will only be updated when an order source is refreshed, whereas "Shipments" and "Fulfillments" can be manipulated by ShipEngine processes.
As ShipEngine exists now, you can create a shipment and a label without being tied to a sales order (that's staying the same). The Shipment model has now been expanded to include
sales_order_items (from multiple sales orders, or just from some of a single sales order).