---
title: "Node.js"
description: "Node.js is a server-side JavaScript runtime. Learn its non-blocking model, the event loop and its uses in APIs and real-time web applications today."
url: "https://nodea.io/en/glossary/node-js"
lang: "en"
updated: "2026-07-13"
---

# Node.js

> Node.js is a runtime environment that lets you execute JavaScript outside the browser — on the server. Thanks to its non-blocking I/O model it excels at scalable network applications.

**Node.js** is an open-source runtime environment that allows [JavaScript](https://nodea.io/en/glossary/javascript) code to run outside the browser — on the server. It is built on the V8 engine (the same one that powers Chrome) and lets you use a single language on both the front end and the back end of an application. Since its 2009 release it has become the foundation of many modern web stacks.

## How Node.js works

Node.js's defining feature is its non-blocking, asynchronous I/O model based on an event loop. Instead of creating a separate thread for each request and waiting for an operation to finish (for example a database read), Node.js dispatches it and immediately moves on to other tasks, handling the result once it is ready. As a result, a single process can efficiently serve a very large number of concurrent connections while using few resources.

The Node.js ecosystem is built around the [npm](https://nodea.io/en/glossary/npm) package manager, which provides access to hundreds of thousands of ready-made libraries. Node.js underpins popular back-end frameworks such as [Express.js](https://nodea.io/en/glossary/express-js), as well as front-end tooling (bundlers, transpilers) and full-stack frameworks like [Next.js](https://nodea.io/en/glossary/next-js).

## Practical application

Node.js is especially well suited to network-intensive applications: APIs and REST services, real-time apps (chats, notifications, WebSocket), microservices and tools handling many simultaneous connections. It is less optimal for CPU-heavy computation, which can block the event loop.

Running a Node.js application requires an environment where the process stays up continuously, so typical PHP shared hosting will not do. The natural choice is a [VPS](https://nodea.io/en/glossary/vps) or dedicated server, which gives full control over the environment, the process manager and the Node.js version — letting you keep the application running stably in production.

### Is Node.js a programming language?

No. Node.js is a runtime that lets you execute code written in the JavaScript language outside the browser, on the server. The language itself remains JavaScript — Node.js provides it with the V8 engine plus access to the file system, network and external libraries installed via npm.

### What hosting does a Node.js app require?

A Node.js app runs as a continuously running process, so it will not work on typical PHP shared hosting. You need a VPS or dedicated server, or a platform with a Node.js runtime, where the application process can be started and kept alive, for example by a process manager.

## Related

- [JavaScript](https://nodea.io/en/glossary/javascript)
- [npm](https://nodea.io/en/glossary/npm)
- [Express.js](https://nodea.io/en/glossary/express-js)
- [Next.js](https://nodea.io/en/glossary/next-js)
- [VPS](https://nodea.io/en/glossary/vps)

---

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