The Paymentwall Mint Android SDK by Paymentwall allows to accept MINT ePins in an application. It works by clicking the "Buy" button, permitting the developer to be notified from the backend and the user to complete a payment entering the ePin.
Revel Systems API makes it possible to run a cash register, a restaurant and a mobile point-of-sale system with an iPad as the center of the user interface. Check out what Revel has to say about the API on their website.
The Scout API, by T3, enables 3rd parties to take advantage of the context the company brings to advertising. Added to location sensitivity, which has been employed by the likes of Walgreens and others geofencing their stores, Scout brings weather, time, speed and orientation. Scout joins a list of 274 advertising APIs in our directory. Public documentation is unavailable; interested developers can contact firstname.lastname@example.org.