Until today, the VISA network was “extremely closed” VISA executives pointed out. And it’s true: financial institutions are typically very difficult to work with because they are (rightly so) extremely paranoid about their network security.
The 155 individual API are RESTful services which are available over the (secure) web. This makes it agnostic from languages that developers want to use and it frees VISA from having to manage many different libraries, although it’s not completely excluded if partners need some help there.
VISA will also offer a sandbox for developers to test with, using dummy data and virtual money. It’s completely normal to offer debugging tools like this to developers since no-one wants to try with real financial transactions.
All the information related to this new platform will be available at developer.visa.com, and VISA is showing some early projects built with close partners, like Capital One, who used the pre-release version of the platform. You can follow the SF event LIVE on this page.