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

Question

I find it hard to find this from the documentation. I have a code that I inherited that should receive the payment amount from an IPN Paypal transaction. It expects the variable "auth_amount" from the Paypal IPN, but does not receive this field. This looks from Paypal docs, as if I should use the "mc_gross" field, which is indicated as "The total amount of the customer’s payment, before deducting the transaction."

Paypal IPN docs describe the "auth_amount" field as the "authorization amount", which means little to me.

I'm going to change it to use mc_gross, but I just want to check first that I will not miss something stupid?

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 The full amount of the payment, before the transaction fee is deducted. Equivalent to payment_gross for payments in US dollars. If this amount is negative, it means a refund or cancellation, as well as these payment statuses may be the full or partial amount of the original transaction.