Here is an interesting post on API from Guardian The application programming interfaces (API) economy has arrived and is booming thanks to the role it plays in cloud computing . But what are APIs and why do they matter for businesses today? Put simply, APIs facilitate communication between applications. Previously, APIs fuelled the growth of consumer-oriented applications such as Facebook, Twitter and LinkedIn. For example, Twitter's popularity is largely because users can interact with the network through multiple channels and devices, made possible by APIs. But these interfaces are no longer the preserve of the consumer world. As a result of trends such as bring your own device (BYOD), employees, partners and customers alike want to connect to corporate services and data. Moreover, they expect to do this via the cloud and a host of mobile applications. Defining APIs Lets explore APIs a little more. In a business context, they can be thought of as Lego blocks,