How should I automate user creation after an online payment, and recomendations for payment systems [closed]

Question

I'm making a very small and simple software, which I want to sell with the Software as a Service model.

I have a lot covered, but cannot understand from the paypal page how to get information about the transaction. Once the transaction has been carried successfully, I have to create a user and send that user his login information.

Where can I find more information about how to do this? what about recomendations? do any of you recommend a different online payment service that makes this easy?

Answer 1

For PayPal, you would use Instant Payment Notification:

Instant Payment Notification (IPN) is PayPal's message service that sends a notification when a transaction is affected. Once IPN is integrated, sellers can automate their back office so they don’t have to wait for payments to come in to trigger order fulfillment.

..

As PayPal’s interface for handling purchase confirmation and server-to-server communications, IPN can also be used to manage and customize a variety of APIs and communications, including: * Customize your website's response to customer purchases in seconds * Notify sellers who deal mostly in software downloads and other digital, online goods

More about IPN here: https://www.paypal.com/ipn

And developer docs here: https://cms.paypal.com/cgi-bin/marketingweb?cmd=_render-content&content_ID=developer/e_howto_admin_IPNIntro