This is easy. When making the API call that creates the payment order, make sure to use the optional parameter ServiceId with the value ‘4’. This will instruct Viva Payments to e-mail a notification with the payment order to your customer.
Don’t forget to include your customer’s e-mail address in the appropriate parameter, or else your notification will never be sent!
When sending Payment Notifications via the API, it is important to set a valid expiration date by using the optional parameters ‘ExpirationDate’ or ‘PaymentTimeOut’. Give your customers enough time to complete the payment, as they may wish to pay you by cash.