How is inventory tracked across several warehouses?

Ship from the closest stock location. Automatically. Multiple stock locations per network or per location. An order pulls from the warehouse that has it, nearest the buyer, and splits when it must. Counts roll up per warehouse and in total, and the routing rules decide which floor decorates what came from where. A location that holds stock in two cities ships each order from the one closest to the buyer, and the label prints where the picking happens. Set a warehouse per store where an account's inventory lives in one place. Counts are live on every store selling from that stock.

What it used to cost you: One warehouse doing all the shipping while the other sat full.

The feature is called Multi-warehouse. It runs on the same rails as everything else here: one catalog, one price list, one cockpit, your name on the front.