We are planing to implement an online payment process once the user submit an application.

The Application form was built using Nintex form.

Question:

Mainly, we need to redirect the user to the payment application once he submit the application. so we need to take a reference from the submitted application to pass it to the payment app.

The problem that if we use Redirect URL option available with Nintex form that will not help because it doesn't allow to put calculated value or variable as a query string .

On the other side, handle the click on the submit button won't help, because the JavaScript will run before saving the form. so in case if any validation stop saving the form, that couldn't be handled. 

Could we have an idea how should we implement that?!