What is a JSON API?
A JSON API is a type of web API (Application Programming Interface) that uses JSON (JavaScript Object Notation) as the format for sending and receiving data between a client (like a web app or mobile app) and a server.
How It Works:
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The client makes an HTTP request (like GET, POST, PUT, DELETE)
-
The server responds with data in JSON format
Why JSON?
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Lightweight and fast
-
Easy to read and write
-
Works well with JavaScript
Commonly Used In:
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REST APIs
-
Frontend-backend communication
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Mobile apps (iOS/Android)
-
Microservices
Use Cases:
| Action | Method | Endpoint | Description |
|---|---|---|---|
| Get all users | GET | /api/users |
Fetch user list |
| Get single user | GET | /api/users/1 |
Fetch user with ID = 1 |
| Add user | POST | /api/users |
Add a new user |
| Update user | PUT | /api/users/1 |
Update user with ID = 1 |
| Delete user | DELETE | /api/users/1 |
Delete user with ID = 1 |
Example :
const express = require('express');
const mysql = require('mysql2');
const app = express();
const connection = require('./db');
app.use(express.json());
// Fetch users
app.get('/api/users', (req, res) => {
connection.query("SELECT * FROM users", (err, results) => {
if (err) return res.status(500).send(err);
res.json(results);
});
});
app.get('/api/users/:id', (req, res) => {
const user_id= req.params.id;
connection.query("SELECT * FROM users where id= ?",[user_id], (err, results) => {
if (err) return res.status(500).send(err);
res.json(results);
});
});
//DELETE user
app.delete('/api/users/:id', (req, res) => {
const user_id= req.params.id;
connection.query("delete FROM users where id= ?",[user_id], (err, results) => {
if (err) return res.status(500).send(err);
res.json({ message: 'User deleted' });
});
});
// Update user
app.put('/api/users/:id', (req, res) => {
const user_id= req.params.id;
connection.query("update users set name=? where id= ?",[req.body.name,user_id], (err, results) => {
if (err) return res.status(500).send(err);
res.json({ message: 'User updated' });
});
});
// Insert user
app.post('/users', (req, res) => {
const { name, email } = req.body;
connection.query("INSERT INTO users (name, email) VALUES (?, ?)", [name, email], (err, result) => {
if (err) return res.status(500).send(err);
res.json({ message: "User added", id: result.insertId });
});
});
app.listen(3000, () => console.log("Server running on port 3000"));
Request :
GET /api/users
Response:
[
{
id: 3,
name: "Smith Doe",
email: "[email protected]"
},
{
id: 4,
name: "smith doe",
email: "[email protected]"
},
{
id: 5,
name: "roberts joy",
email: "[email protected]"
},
{
id: 6,
name: "rose donaldo",
email: "[email protected]"
}
]
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