An Application Programming Interface (API) is a piece of software that acts like a messenger between two applications. If you are using one application but require information from another one, the API will go fetch it for you. You can also think of it as an intermediary that enables two computer applications to interact with each other and enable a particular function.
When you use an application on your smartphone to send a text message, it’s the API that tells a server what you want to do. The server then performs the action and sends back the data to your phone, which is then able to proceed and send the text message.
Other interesting terms…
