Backorders in Magento 2
Backorders functionality is supported by Magento 2 out-of-the-box. Go to Stores – Configuration – Catalog – Inventory – Product Stock Options tab.
In the ‘Backorders’ section select the necessary option:
- No backorders disables backorders in your store;
- Allow Qty Below 0 shows the product as In Stock even when the product reaches qty = 0;
- Allow Qty Below 0 and Notify Customer shows the product as In Stock and dispays the appropriate message on the shopping cart.