An API (Application Programming Interface), is a bridge that facilitates communication between two different software systems. Think of an API as a restaurant menu; The menu tells you what dishes they have. These are the services . You (the user or program), place an order. This is making a request. The kitchen, which is the system, prepares the order, which is processing the request. The waiter, who is the API, brings you the prepared food, which is the response, without you needing to know how it was cooked.