For a Paypal IPN what's the difference between auth_amount and mc_gross?

Question

I'm having a hard time finding this out from the documentation. I have some code I've inherited which needs to get he payment amount from a Paypal IPN transaction. It's expecting the variable "auth_amount" from a Paypal IPN but is not getting passed this field. It looks to me from the Paypal docs as though I should be using the field "mc_gross" which is labelled as "Full amount of the customer's payment, before transaction fee is subtracted.".

The Paypal IPN docs describe the "auth_amount" field as "Authorization amount", which doesn't mean much to me.

I'm going to change it to use mc_gross, but I just want to check first that I'm not missing something silly?

Thanks!

Answer 1

Check this out: https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_html_IPNandPDTVariables

mc_gross Full amount of the customer's payment, before transaction fee is subtracted. Equivalent to payment_gross for USD payments. If this amount is negative, it signifies a refund or reversal, and either of those payment statuses can be for the full or partial amount of the original transaction.