QuickBooks Bill Payment API
A BillPayment object represents the payment transaction for a bill that the business owner receives from a vendor for goods or services purchased from the vendor. QuickBooks Online supports bill payments through a credit card or a checking account. BillPayment.TotalAmt is the total amount associated with this payment. This includes the total of all the payments from the payment line details. If TotalAmt is greater than the total on the lines being paid, the overpayment is treated as a credit and exposed as such on the QuickBooks UI. The total amount cannot be negative.