Its been slowly creeping up on us, creating exciting new possibilities for our applications; APIs are changing the face of the Web. Since 2005 Programmable Web have been tracking SOAP and REST APIs available to the public. In 2005 they tracked 105 APIs, the prominent ones being from Amazon, Google, SalesForce and eBay. By 2008 this number had grown 6-fold to 601 APIs with social and traditional media seeing value in opening up their data to third parties. By the end of 2010 developers had over 2,500 APIs at our disposal. While forward thinking companies like Zappos published a REST API, we also saw government and brick and mortar retail join the fray. Tesco allows developers to order groceries, Instagram created a Twitter for pictures, Face offers facial recognition as a service and you can create telephony applications with a few calls to Twilio. In 2011 we’re seeing the number of public APIs climb towards 5,000, there has never been a better time to build killer applications.