API stands for Application Programming Interface. It is a way for different applications to communicate with each other.
When your JavaScript app needs data from a server — such as user details, products, or weather information — it uses an API to request that data.
APIs are the backbone of modern web development. Almost every real-world application uses APIs to connect the front-end with the back-end.
Why APIs Are Important
- They connect front-end and back-end systems
- They allow apps to share data
- They make websites dynamic
- They power mobile apps and web services
- They are used in almost every modern project
Without APIs, web applications would not be able to use real data.
This analogy helps understand how APIs work.
The client does not talk directly to the server’s internal system.
It always goes through the API.
In real applications, this would be an actual request sent to a server using JavaScript.
Later in this chapter, you will learn how to use fetch() to make real API calls.
These examples show the basic idea of how APIs work — sending requests and receiving data.
By understanding what an API is, students gain the foundation needed to work with real servers, databases, and professional web applications.