What are APIs?
A Simple Scenario
The easiest way to think about APIs is with a simple analogy:
When you go to a restaurant, you typically ask the waiter for food, drinks, and to eventually pay the bill. You talk to the waiter instead of walking into the restaurant and analyzing the oven, stove, chefs, and all of the ingredients to see what they can make for you to order. This would take a ton of time and if every person who wanted to eat at the restaurant wanted to do this, it would get overwhelming pretty quickly. The waiter is basically shielding you from all of the complicated things that happens behind the scenes. Waiters are the interface that shows you all of the services the restaurant has to offer, giving you a way to interact with the restaurant without dealing with complexity. (Shoutout to waiters!)
APIs are basically like restaurant waiters!
The most popular APIs are ones that you actually may use on a daily basis. They are: Apple's Siri, Amazon's Alexa, and Google's Assistant. These voice assistants shield you from the complexity of looking something up, configuring something in your settings, and much more.
Typical Use Cases
Whenever two Apps need to talk to each other, there's an API. Each respective app doesn't want to know about every single complexity about the app it;s trying to connect with. It's a waste of time, in a world where tech wants to be faster. So when you want to show the weather for a specific area on your calendar app, or want to show daily stock market updates on your investment app, there's an API making sure that's possible!