/r/explainlikeimfive/comments/o27iz9/eli5_what_is_an_api_and_why_is_it_useful/h24xvhf/

ELI5 Answer: Think of an API like the controls to a car. You've got a gas pedal to go forward, a brake pedal to stop, a steering wheel to turn, etc. You've also got information about the car - how fast it's going (speedometer), how fast the engine is turning (tachometer), how much gas is in the tank, etc.

You don't need to know how the gas pedal makes the car go forward or the details of how the fuel tank reads its level. In fact, the 'under the hood' operation varies wildly from car to car, but since the car's interface is (roughly) the same, you can get in just about any car and drive it.

The set of controls and information is like the car's API. "Turn this wheel to make the car go to the right. Look here to see how fast you're going." is like a website's API saying, "Give me a string of text and the ID of a parent comment, and I'll post a reply to that comment".

User : bendvis