PayPal generate invoice and notify application after payment

Question

I would appreciatte if someone helps me to clarify some PayPal concepts. I'm using PayPal to send/receive payments and I want to offer the users the possibility of get an invoice for the payments. So, right now I'm using the Invoicing Service API for the payments I receive, I call the service and get the URL of the invoice for the user and here is muy first question: once the user pays the invoice, how do I get notified of this in my application (without having to login into PayPal and check by myself)?
Second: in the Integration Guide it says "PayPal sends IPN messages for invoice payments and for invoices cancelled by the buyer..." is IPN the only option to get notified of a payment in my application? Beyond this, I've start reading about IPN and testing the IPN Simulator, but after select all of the items in the combo "Transaction Type" I couldn't see the transaction type "invoice_payment" mentioned in the Invoicing Service API, so which type of transaction should I configure?
Thanks in advance, regards.

Answer 1

You can try using the Web Accept. Basically, the IPN simulator is used to test your IPN Listener whether it can listen to the message that sent by PayPal. It does not sent any a real message to your listener. For the invoice payment, it will return invoive_payment. You can have a try on your end.