Paypal Notify_url with custom param

Question

As all we know there is a custom param that allow us to retrieve custom data when an ipn notification come from paypal.

But also, I am using a couple of params in the notify_url, and those params sometimes get lost, and when paypal send to me the ipn notification, it comes without one of those params. The strange thing is that one of the param come correctly.

So, first question is: Can I use custom params in the notify_url like:

 notify_url = "www.mydomain.com/paypal/ipn/?param1=one&param2=two"

I suppose that I can do it, because it fails 1 in 20 times on my application, so I do not know if it is because it is not supported by some browsers or something like that, or maybe it is a bad habit I should quit.

And sometimes paypal send the ipn notification to:

 notify_url = "www.mydomain.com/paypal/ipn/?param1=one"

Without the second param...

And if I can do it, do you have any clue about what it is happening here...

Thanks!

Answer 1

I always avoid sending data to IPN as URL parameters. There are various reasons it may not come through, which means there's no guarantee it'll work correctly every single time.

Instead, use the CUSTOM parameter like you said. If you need to pass more than a single value you can send it as an NVP string just like you would on your URL. Then just parse those values back out of the CUSTOM value within your IPN script.

Alternatively, you could save all of the data you're going to need in your database and then send the record ID in the CUSTOM parameter over to PayPal. Or you could use the INVNUM parameter if that makes sense for you.

Then in your IPN script you pull that data back out of the database based on that record ID. This way you're always sure you'll have it available and won't have to worry about losing URL params along the way.