The PaySimple Go SDK by Aaron O. Ellis allows to interact with API data to integrate payments and billing features into applications. Available tests to work with account, authorization, customer, and payment.
From billion dollar companies to the neighborhood coffee shops, merchants of all sizes are seeking new ways to offer secure and affordable mobile payments systems that expand their ability to conduct business. The PayPal API got its start this way, first with online auctions, then with thousands of websites and individuals. It's now one of over 150 payment APIs, many of which exist outside of traditional finance.
Payleven launched a developer suite to enable 3rd-party apps and POS systems integration with payleven payment solutions. The suite includes App Pay and Point Pay which allow for solutions that bypass card reader requirements and those that utilize card readers. API and SDK options are available.