> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# NodeJS Application Overview
> This article provides an overview of Node.js, its features, npm, and a typical project structure for building applications.
In this lesson, we’ll explore [Node.js][Node.js]—an open-source, cross-platform JavaScript runtime—and see how it powers custom [GitHub Actions][GitHub Actions] workflows. You’ll learn about its core features, the built-in package manager, and a typical project layout.
## What Is Node.js?
[Node.js][Node.js] is a JavaScript runtime built on Google’s high-performance [V8 engine][V8]. It lets you run JavaScript outside the browser, so you can build server-side apps, CLI tools, and more—all with the same language you use in the browser. Node.js supports Windows, macOS, and Linux.
For production environments, use the Long-Term Support (LTS) version of Node.js. Manage multiple versions easily with tools like [nvm](https://github.com/nvm-sh/nvm).
## Node Package Manager (npm)
When you install Node.js, you also get [npm][npm]—the package manager that helps you discover, install, and manage JavaScript libraries and dependencies. With npm you can:
* Share code with the community via the npm registry
* Install and update packages with a single command
* Define project scripts for testing, building, and running your app
## Sample Node.js Project Structure
A minimal Node.js project often includes these three files:
| File | Purpose |
| ------------ | --------------------------------------------------- |
| package.json | Metadata (name, version) and dependency definitions |
| index.js | Application entry point and core logic |
| test.js | Automated tests for your code |
To set up your project:
```bash theme={null}
# Install all dependencies listed in package.json
npm install
```
After installation, npm creates a `node_modules` folder with all packages you need.
## Common npm Commands
| Command | Description |
| ----------- | ------------------------------------- |
| npm install | Install project dependencies |
| npm test | Run tests defined in `test.js` |
| npm start | Launch the application (e.g., server) |
```bash theme={null}
# Verify your environment
$ node -v
v18.16.0
$ npm -v
9.8.1
# Install dependencies
$ npm install
# Run tests
$ npm test
# Start the application
$ npm start
App listening on port 3000
```
Once the application is running, open your browser and navigate to [http://localhost:3000](http://localhost:3000).
## Links and References
* [Node.js][Node.js]
* [npm][npm]
* [V8 JavaScript Engine][V8]
* [GitHub Actions][GitHub Actions]
[Node.js]: https://nodejs.org/
[npm]: https://www.npmjs.com/
[V8]: https://v8.dev/
[GitHub Actions]: https://docs.github.com/en/actions