The Pin Payments PHP SDK by Pin Payments allows API interaction to implement credit card features into applications. It provides a sample code that presents a purchase with description, amount, and currency.
After beta testing for almost a year, the Facebook Credits API is finally being opened to all developers. Before beta testing the service had been in very limited alpha testing for over six months before that. On July 1st, more than two years after the social networking site started working on the system, all Facebook-based games that process payments will be required to use only Facebook Credits. The 350 applications granted early access already account for 70% of such transactions. Facebook credits can be purchased by users at a rate of $0.10 each (with an additional 10 free when buying 100) and redeemed by application developers for $0.07, leaving Facebook with the balance.