An introduction to APIs
You can think of APIs as a set of rules that will allow one piece of software to interact with another. A quick example of the usage of an API would be the weather app on a smartphone connecting with the weather system to get the current weather or a forecast of the weather.
An easy way to think of an API, besides a mechanism for different systems to communicate, is to think of a contract. The documentation of an API will specify how a system can connect with and talk with the system, what it is allowed to do, and how often.
Systems that maintain an API will often act as a sort of client and server type arrangement. A REST API is one of the most popular types of API today. REST stands for representational state transfer. The major pro of this type of API is that it is stateless. Statelessness means that servers do not save client data between requests. The requests that are sent to the server will remind you of a URL. A generic REST API call might look...