Developers can use an application programming interface, or API, to build software applications that use standardized rules for telling software components how to interact with one another. That way, those components can share data and functions. Open APIs, as opposed to private APIs, are those that have been released publicly for developers to use. For example, with Doctors on Demand, physicians can send a patient’s prescription to the nearest pharmacy. To show the closest pharmacies on a map within the Doctors on Demand app, the company relies on Google Maps APIs.