What is an API
This guide is a non-technical explanation of API’s, it focuses on explaining the idea rather then 100% technical correctness.
What does API mean?
API is the shortcut for Application Programming Interface. It allows two applications to talk with each other as an intermediary. Each time you use messenger, checking the weather on your phone or using an app like instagram, your application (e.g. Mobile App) might communicate to an API to get or modify the data in an other application (Server).
What is it doing?
As the definition above already states, an API sits in between various components of a software or between different applications. It interpretates and translates the output data of one component in a pre-defined way, so that other components are able to process it.
An illustrating example
Imagine you are visiting a restaurant. After having a seat the menu is handed with a list of available meals you can order from. Those meals are being prepared in the kitchen, which is the „system“ your order is being processed and transformed into your meal. So, how do you take your order to the kitchen?
You might guess it: Call the waiter! The waiter takes the order to the kitchen where then it’s being made. Afterwards, the waiter brings back your delicious meal.
An API is like the waiter. It takes your order and tells the system what to do. Then it returns the response you asked for.
Advantages of APIs
APIs have many advantages. First of all it provides stability as a layer between users/compoments and the system. With an API communicating you are able to change the system in the back without disturbing the user. A second advantage evolves out of security reasons. Sitting in-between the system and components/users it builds a protection layer since information can only be carried to the „vulnerable“ system in a way the API is allowed to do due to its definition. I.e. it could be prohibited for the API to write information into the system (Read only) so if an external force is trying to do that it is not going to work.
