Cloud Cart Connector will skip adding duplicate invoices to QuickBooks. If Cloud Cart finds a matching invoice for the payment and the invoice has a balance, then Cloud Cart will insert a payment.
What field in Authorize.NET should match the QuickBooks order number field?
In Authorize.NET, each transaction has a field called invoice number. Entering an invoice number is optional. In the event the invoice number is empty, Cloud Cart uses the transaction ID as the QuickBooks order number. Therefore, the invoice number field must match an existing order in QB.
Here is a printed receipt from an Authorize.NET transaction:
Here is a matching invoice in QB:
How do I set-up the integration?
On the my connections page of Cloud Cart, set up the connection with your ordering system. At the configure page, select invoices only from the first drop down. At the complete page, click my connections and add a new connection for Authorize.NET. Select invoices payments if paid from the first drop down. Your Authorize.net connection will find the invoice and skipping adding it, then it will find the payment to that invoice number and apply the payment.