The BlueSnap Payment iOS SDK by BlueSnap allows API communication to implement payment features into eCommerce applications. It includes a link to download the kit, along with guides to integrate from download to initialization.
Over there, by the gum and the tabloid magazines, there's an API. Literally, it's a piece of plastic, but behind it is a company and the APIs that company uses to make the whole operation work. Blackhawk, a subsidiary of Safeway, distributes gift cards for many big-name stores in 90,000 retail locations. And while the cards have always been supported by backend systems, mobile is moving this ten year-old company to an open API approach.
APIs continue to work their way into just about every part of the digital economy. The latest example is Subledger, which offers a suite of APIs that let developers integrate accounting functionality into their applications.