How to Install JSON Server on a Windows Computer

When building or testing front-end applications, having a lightweight backend for mock data can save a lot of time. That’s where JSON Server comes in. It allows you to set up a fully functional REST API using a simple JSON file, without the need for a real database or backend code.

In this guide, we’ll walk through how to install and run JSON Server on a Windows computer step-by-step.

What You’ll Need

Before you begin, make sure you have the following:

A Windows 10 or Windows 11 computer
Node.js and npm (Node Package Manager) installed
A stable internet connection
Basic familiarity with the Command Prompt or PowerShell

If you don’t have Node.js installed, download it from the official Node.js website and install the LTS (Long-Term Support) version. The installer includes npm by default.

Step 1: Verify Node.js and npm Installation

Once Node.js is installed, open Command Prompt or PowerShell and run the following commands to verify the installation:

node -v
npm -v

You should see version numbers for both commands. If you don’t, restart your computer and try again.

Step 2: Install JSON Server Globally

You can install JSON Server globally on your system using npm. In your terminal, run:

npm install -g json-server

This command will download and install the latest version of JSON Server and make it available system-wide.

To verify the installation, run:

json-server --version

If it displays a version number, JSON Server has been installed successfully.

Step 3: Create a JSON File for Your Data

Next, you’ll need a data source for your mock API. Create a new folder where you want to store your project files, for example:

mkdir json-server-demo
cd json-server-demo

Inside this folder, create a new file named db.json and add some sample data:

{
  "posts": [
    { "id": 1, "title": "Hello World", "author": "John" },
    { "id": 2, "title": "JSON Server Guide", "author": "Ajoy" }
  ],
  "comments": [
    { "id": 1, "body": "Nice post!", "postId": 1 }
  ]
}

This file acts as your database. JSON Server will read it and create API endpoints automatically.

Step 4: Start JSON Server

Now it’s time to start your local server. Run the following command inside the same folder as your db.json file:

json-server --watch db.json

You’ll see output similar to this:

\{^_^}/ hi!

Loading db.json
Done

Resources
http://localhost:3000/posts
http://localhost:3000/comments

Home
http://localhost:3000

Your fake REST API is now live at http://localhost:3000.

Step 5: Access and Test Your API

Open a browser and navigate to:

http://localhost:3000/posts

You should see the JSON data from your db.json file displayed in the browser.

You can also use tools like Postman, Insomnia, or cURL to send GET, POST, PUT, PATCH, and DELETE requests to your API — just like you would with a real backend.

For example:

GET /posts returns all posts.
POST /posts adds a new post.
DELETE /posts/1 removes the post with ID 1.

Step 6: Optional – Change the Default Port

By default, JSON Server runs on port 3000. You can change this by using the --port flag:

json-server --watch db.json --port 5000

Your API will now be accessible at http://localhost:5000.

Wrapping Up

JSON Server is one of the easiest and fastest ways to create a mock REST API for testing and front-end development. With just Node.js and a JSON file, you can simulate backend behavior, test endpoints, and integrate your front-end projects — all without setting up an actual database.

Once you’re familiar with it, you can even customize routes, add middleware, or use JSON Server as part of a more advanced development workflow.