API

What is API?

API stands for Application Programming Interface. It is a bridge that allows two applications to communicate and exchange data with each other. APIs are used to send requests and receive responses between frontend and backend applications. They help applications fetch, store, update, and delete data from the server or database. APIs are widely used in web applications, mobile applications, and cloud services. For example, a React frontend uses APIs to get data from a Spring Boot backend.

For example:

=> React frontend
=> Spring Boot backend
=> MySQL database

The frontend cannot directly access the database.
So it sends a request through an API, and the backend returns the response.

Simple Flow

Frontend → API → Backend → Database

Real-Time Example

Consider a food delivery app.
=> The mobile app needs restaurant data
=> The data is stored in the server/database
=> The app requests data using an API
=> The server sends the response
---> So APIs help different applications communicate with each other.

Why Do We Use API?
1.Communication Between Applications

APIs allow different applications to communicate.

Example:
React ↔ Spring Boot
Mobile App ↔ Server
Website ↔ Payment Gateway

2.To Fetch Data

APIs are used to get data from the server or database.
Example:

GET /products
   This returns all products.

3. To Send Data

APIs are used to store data in the database.
Example:

POST /products
       This adds a new product.

4. To Update Data

Example:

PUT /products/1
         This updates the product with ID 1.

5. To Delete Data

Example:

DELETE /products/1
          This deletes the product with ID 1.