Ordering out-of-stock products
By default, your wholesale customers can add items that are out-of-stock to their cart. This option is useful when you know that your out-of-stock products will likely be available before your customer makes payment.
If you do not want your customers to submit orders that contain out-of-stock products, then you can disable Out-of-stock items on the Settings page in the Wholesale channel.
There is a slight chance that a product can be out-of-stock when your wholesale customer tries to pay for their order. For example, a product can be in-stock when your customer submits a draft order, but be sold out when they open their invoice to pay for it.
If you track inventory using Shopify, then your inventory is checked before your customer pays for the invoice. When your inventory doesn't contain enough product to fulfill the order, the following events occur:
If the product is in-stock, but the amount available is less than what the customer ordered, then your customer's order changes so that the number of items ordered matches your inventory. For example, your customer orders 10 fidget spinners, but when they are ready to make payment, only 5 exist in your inventory. Their order changes automatically so that your customer orders and pays for 5 fidget spinners.
If the product is out-of-stock, then the customer is instructed to contact you, the merchant. They cannot pay for this order or change it. You must open their draft order in the Shopify admin, remove the out-of-stock products, and resend the invoice.
If you accept your customer's payment by clicking Pay with credit card on the draft order, then the inventory check occurs after the payment completes. If any product is out-of-stock, a warning appears at the top of the order.