Localhost 3000 (original) (raw)

Last Updated : 23 Jul, 2025

Localhost:3000 is a default port used by the web servers. It is a **local development server that runs on **port **3000. It is very commonly used by experienced as well as beginner and intermediate-level developers when they working on a web application. Developers use localhost:3000 to see the preview of the developed application and test it according to the requirements for responsiveness and other parameters before deploying it to production.

Let us understand localhost:3000 by breaking it down:

• **localhost: It refers to the hostname or the current device you are using for development purposes.
• **3000: It is the port number on which the created development server is configured to listen.

Let us dive deeper into the concept of localhost:3000 by understanding the below points one by one:

How to start the localhost:3000 server on your machine?

To start the localhost:3000 server you must need to have a service that operates on the localhost:3000 port like **ReactJS, **NodeJS, **VueJS, **AngularJS, etc. If you are working with any of the mentioned services, then you need to type a command inside the terminal of your IDE or command prompt based on the service you are using.

Commands for different services are listed below:

• **Node.js****:** If you have node.js installed on your machine with **Node Package Manager(npm). You can use the tools like **http-server or **live-server to start the localhost:3000 development server with the help of below commands:

// Install tools globally
npm install -g http-server/liver-server
// Navigate to your project
cd pathOfYourProject
// Start the server at port:3000
http-server/live-server -p 3000

• **ReactJS****:** In the case of ReactJS, you don't need to install the server externally. If you are creating a react app using **create-react-app it automatically creates a development server. You just need to run the below commands to start the server.

// Navigate to your project directory
cd pathOfYourProject
// Start the server
npm start

• **AngularJS****:** The angular app also comes with development server, you just need to create angular app using the Angular CLI and run the below commands.

// Navigate to your project directory
cd pathOfYourProject
// Start the server
ng serve
//By default, angular app run on port 4200 use below command to change it
ng serve --port 3000

How to create development server in ReactJS?

Follow the below steps to create and start development server in ReactJS:

• **Step 1: Create react app using the **npm create-react-app command by specifying the name of the project after it.

npm create-react-app projectName

• **Step 2: Navigate to your current project folder.

cd pathToYourProject

• **Step 3: Create files inside the **src folder and run the server using below command.

npm start

**Example: The below code can be used as a template code for your file.

JavaScript `

// App.js file

import React, { useState } from 'react';

const App = ({ prop }) => { const [isHidden, setIsHidden] = useState(false) function btnClickHandler() { setIsHidden((prev) => !prev); }

return (
    <div style={{ textAlign: 'center' }}>
        <h1 style={{ color: 'green' }}>GeeksforGeeks</h1>
        <h1>Hey {prop}!</h1>
        <h2>Welcome to GeeksforGeeks</h2>
        {
            isHidden &&
            <h3>A Computer Science Portal.</h3>
        }
        <button onClick={btnClickHandler}
            style={
                {
                    backgroundColor: "green",
                    color: '#fff',
                    padding: '15px',
                    cursor: 'pointer',
                    border: 'none',
                    borderRadius: '10px'
                }}>
            Click to toggle more page content
        </button>
        {
            isHidden &&
            <p>
                This content is toggled dynamically using
                click event with button.
            </p>
        }
    </div>
);

};

export default App;

`

**Output: