Authorize.net offers a "Silent POST" feature for their Automated Recurring Billing. It's supposed to POST data to a url of your choosing, telling you whether they were able to charge the customer, how much, etc. The problem is, it isn't very well documented.
x_first_name
, x_amount
- I've seen code that uses those values - but since I can't actually get it to send a response, I'm not sure.Better late then never: All About Authorize.Net’s Silent Post