Application Programming Interface (API)

An application programming interface (API) is a software intermediary that allows applications and software services to communicate and exchange data with one another. This enables a software service to access data from another without the developer needing to know how that other service works.

By allowing applications to pass data back and forth, APIs enable users to log in to websites using their existing Google, Facebook or Twitter accounts, removing the need to create logins for new websites or applications. The Google Maps application also uses APIs to provide users with directions and highlight points of interest, while third-party payment providers like PayPal leverage APIs to allow secure payment on many ecommerce websites.
Since an API enables applications to essentially “talk” to one another, it allows them to seamlessly assimilate and embed data from multiple sources, giving users smooth and integrated experiences. It also ensures you can embed relevant up-to-date information from other applications and software services.
An API is a set of guidelines that specifies how applications, systems and machines can communicate with one another. Web APIs reside between applications and web servers; an API call made by a user will instruct their application to perform an action, after which the application will send a request to the web server using an API call. This call will allow the application and web server to exchange information with no issues.