JavaScript

JSON Server is a simple tool that lets you create a full fake REST API with a single JSON file. It’s widely used by frontend developers to simulate backend functionality during development and testing.

✅ It allows you to perform CRUD operations (Create, Read, Update, Delete) on local JSON data, just like working with a real database.

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🚀 Why Use JSON Server?

• No backend setup needed
• Instantly create an API with a JSON file
• Supports RESTful routes
• Quick to set up and start using
• Great for mock data testing

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🛠️ Installation

🔸 Install via npm (Node.js required)

npm install -g json-server

You can also install it locally for a specific project:

npm install json-server --save-dev

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📁 Step-by-Step Example

🔹 1. Create a JSON file (e.g., db.json)

{
  "users": [
    { "id": 1, "name": "Alice", "age": 25 },
    { "id": 2, "name": "Bob", "age": 30 }
  ]
}

🔹 2. Start the JSON Server

json-server --watch db.json

By default, the server runs at http://localhost:3000

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📡 Available REST API Endpoints

For users in db.json, JSON Server automatically provides:

Method	Endpoint	Description
GET	/users	Get all users
GET	/users/1	Get user by ID
POST	/users	Add a new user
PUT	/users/1	Update entire user
PATCH	/users/1	Update partial user
DELETE	/users/1	Delete user by ID

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✏️ Example Usage with fetch()

GET all users:

fetch("http://localhost:3000/users")
  .then(res => res.json())
  .then(data => console.log(data));

POST a new user:

fetch("http://localhost:3000/users", {
  method: "POST",
  headers: {
    "Content-Type": "application/json"
  },
  body: JSON.stringify({ name: "Charlie", age: 28 })
});

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📂 Folder Structure (Optional Custom Setup)

my-project/
├── db.json
├── package.json
├── index.html
└── script.js

You can also add routes.json to create custom routes.

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⚙️ Extra Features

• Add _sort, _order, _limit, _page in URLs for query handling: /users?_sort=name&_order=asc&_limit=2
• Filter by parameters: /users?age=25
• Search: /users?q=Alice

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✅ Summary

Feature	Details
Use	Fake REST API for development
Setup	Node + npm required
Data source	Single JSON file
Supports	GET, POST, PUT, PATCH, DELETE
Useful for	Frontend devs testing with mock backend

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