Accepting credit cards on your website can be surprisingly tricky business. On one hand, you want to provide a solution that's as secure as possible (read: credit card data is never sent to your sofware), the on the other, you want to user experience to be as smooth as possible (read: allowing users to save and reuse credit cards or setup monthly subscriptions). And on the third hand, you'd like implementing the platform to be simple.
What's a programmer to do?
And then there's the API. To my delight, they offer examples that interact with the API via a curl command line session. This is an excellent practices, as it demonstrates to the programmer just how simple the API is to implement (there's no magic, it's just HTTP requests).
Finally, I love their easy test/production mode switch.
Of course, I've only written a little code to interact with them - so perhaps there's some gotchas I haven't detected yet. And I don't have any visibility into the business side of things (the client just provides me with the account, and I program away). But clearly, these guys are developer focused. Where Authorize.net has a mountain of products and docs to wade through (DPM, SIM, AIM, Oh My!), these guys appear to have a simple and flexible offering. Definitely worth checking out.