Quickbooks:

…such as changes to document status or balances reaching preset thresholds. For example: receipt of pending orders from your shopping cart, stock running low, customer balances reaching a credit limit or order profit margins falling below a preset limit.

…such as create and send a purchase order to a supplier when stock limit falls below a threshold, or automatically create invoices or cash sales from shipped orders.

…such as if enough stock is available process all pending orders, create shipments and send shipping vendor requests.