Node.js is an open-source JavaScript runtime environment. It runs JavaScript code outside of a web browser, allowing web developers to use JavaScript as the back-end of their web applications. Node.js is also cross-platform and runs on Windows, Unix, Linux, and macOS.

Before the introduction of Node.js, JavaScript could only run within a web browser. Websites could use JavaScript to add client-side interactivity on web pages and web applications, but the web server itself needed to use another language, like PHP, for its share of the work. Node.js allows JavaScript code to run server-side, which means that web developers can use one language for both the front- and backend of their web apps.

Web browsers use their own JavaScript engines, while web servers use Node.js
Web browsers use their own JavaScript engines, while web servers use Node.js

Node.js is popular among web developers for several reasons. First, it is efficient for applications that require many simultaneous connections, and can handle many requests at once. It also has a large ecosystem of open-source packages and libraries available through Node Package Manager, which allows developers to easily add new features by integrating existing modules into their applications. Finally, the ability to use one programming language instead of two reduces the complexity of a project and provides an easier learning curve.

NOTE: Node.js uses Google's V8 JavaScript runtime engine, the same engine used by the Chrome web browser.

Updated June 20, 2023 by Brian P.

quizTest Your Knowledge

Which of these protocols was introduced as a secure replacement for Telnet?

Correct! Incorrect!     View the SSH definition.
More Quizzes →

The Tech Terms Computer Dictionary

The definition of Node.js on this page is an original definition written by the team. If you would like to reference this page or cite this definition, please use the green citation links above.

The goal of is to explain computer terminology in a way that is easy to understand. We strive for simplicity and accuracy with every definition we publish. If you have feedback about this definition or would like to suggest a new technical term, please contact us.

Sign up for the free TechTerms Newsletter

How often would you like to receive an email?

You can unsubscribe or change your frequency setting at any time using the links available in each email.

Questions? Please contact us.