How to perform a server to server request with Paypal

[SergeantPepper]

Hi,

I have searched and searched through the Paypal documentation, but didn't find the solution ... however, I believe it is a common task.

On my website people can buy an e-book. They click the 'Buy now' button with a hidden unique ID, successfully pays the amount, and auto return to my website. However, I need to find a way where the unique ID will be send from Paypal back to my server using a different (secret) URL after a successful payment, so I can update my database and automatically send an e-mail to the buyer with their e-book.

Does anybody know the solution to this at Paypal?

Best regards,

Christophe

[PayPal_RobG]

Yes, have a look at PayPal Instant Payment Notifications to receive a server-to-server notification from PayPal which you can subsequently verify and use to update your database / send out your custom email.

IPN works as follows:

1. You create the PayPal and incude a "notify_url". The value for this parameter will be the full URL to a script on your server, called the 'IPN script' or 'IPN handler'.

You can specify an IPN handler as follows for Website Payments Standard

<input type="hidden" name="notify_url" value="http://yourdomain.com/ipn.php

For Express Checkout or Website Payments Pro, simply include the following in your SetExpressCheckout/DoExpressCheckoutPayment or DoDirectPayment API call respectively. NOTIFYURL=http://yourdomain.com/ipn.php

Next:

1. A buyer completes a transaction via PayPal
2. Once the buyer completes the transaction, he/she may close the browser, or return to your website. It doesn't matter.
3. Once the transaction is accepted and processed by PayPal, PayPal will send out a notification to http://yourdomain.com/ipn.php
4. You need to take all POST data that was sent to this script, and POST it back to https://www.paypal.com/cgi-bin/webscr?cmd=_notify-validate
5. If the data you send back matches the data PayPal sent you, a 'VERIFIED' response is returned.
6. If the response is VERIFIED, it's at this point that you would look up the matching transaction/buyer on your end, and update the phpBB thread status appropriately.

Some sample code and documentation for PayPal IPN is available at https://www.paypal.com/ipn/
In addition, some tips on making a secure IPN script are available at https://www.x.com/developers/community/blogs/ppmtsrobertg/securing-your-instant-payment-notification...

Note: If you want to include any custom data along with the transaction which you can read out later, use 'custom'.
<input type="hidden" name="custom" value="xxxxx">
This will also be returned in the IPN POST data sent from PayPal.

Should you run into any issues while implementing IPN, support is available via https://www.paypal.com/mts/