Most third party CC companies do not use a "Perl call" per se, but a simple http (or https) transaction. In other words, a form. You can certainly use LWP and the like to run it yourself. A word of warning: some companies are very browser based, and will return a page directed at the user (e.g. "Hey you forgot your zip code!") instead of a simple valid/invalid code. Shop around, too - prices vary greatly. Most have minor monthly fees (or the low-activity fee- watch out!) as well as the per transaction fee. Figure out your expected transactions per month, and do a lot of shopping around. Your best bet is one without bells and whistles due to the nature of your app (I am assuming that all you need is a simple back-end and you will be doing all the front-end work of gathering the cc#'s and other info)