Current stock as Finale stores it: one entry per product, location, lot and order with quantityOnHand, quantityOnOrder (committed purchase orders) and quantityReserved (committed sales orders). The inventoryitem collection has no server-side filter, so the WHOLE collection is downloaded (one collection read of the 300 per hour; can be large on big accounts, up to the 50,000 character result cap) and filtered here: pass product_id or facility_url. For per-product totals use finale_get_product_stock. GET /{account}/api/inventoryitem/.