What is a Web Service?
A little bit about the Internet of things, mobile apps and other stuff
Assume you have two computers connected to the Internet, both are on the different continents. To communicate with each other they need a unified language. This is a key — the web service is a standardized way for two computers to interact. In the age of the ‘Internet of Things’ (IoT), anything connected to the Internet can be a computer (even your microwave oven).
So computers or devices can use the same API (an application program interface) to understand and interact with each other without any human intervention. We can use API’s in everyday life and don’t know about that (e.g. when we connect a phone to the computer).
REST is just another one way to make the Web Services work. There are also other formats such as XML-RPC, SOAP, etc.
Let’s take a look at REST abilities of Drupal 8.