The Orders API is your one-stop shop for adding rich functionality to payments. You can itemize payments using custom line items or catalog objects, send orders to physical Point of Sale devices to be fulfilled, attach a customer to a payment, and more.
In addition, the Orders API lets you search through all of a seller's past sales and returns itemization data, customer references, and other details from sales made using POS or online.
If you use the Square Orders API with a non-Square payments provider, Square charges a transaction fee. For more information, see Orders API fee structure.
For more information, see the following guides: