Summary  
Node.js is a JavaScript runtime built on Chrome’s V8 engine that executes JavaScript outside of browsers and uses a non-blocking, event-driven architecture for efficient concurrency.

General domain of usage  
Server-side application development

Node.js is a **JavaScript runtime** built on Chrome's V8 JavaScript engine. Unlike traditional JavaScript environments that run in web browsers, Node.js allows you to execute JavaScript code directly on your computer or server, outside of any browser. This means you can use JavaScript to build applications that run on the server side, such as web servers, command-line tools, APIs, and even desktop applications. **Node.js** is especially popular for building scalable network applications because it uses a **non-blocking, event-driven architecture** that can handle many connections at once without slowing down.

**Node.js is commonly used for:**
- Building web servers and server-side applications;
- Creating RESTful APIs for web and mobile apps;
- Developing real-time applications like chat apps and online games;
- Writing command-line utilities and automation scripts;
- Prototyping and rapid application development.

A **"runtime environment"** is a platform that provides everything needed to execute code written in a specific language. **Node.js** is considered a runtime environment because it supplies the engine (`V8`), libraries, and system interfaces required to run JavaScript programs outside the browser.

Definition

Which statement best describes Node.js and its primary use?

Learn how to run JavaScript outside the browser and build backend logic using Node.js. Work with the file system, environment variables, modules, and external packages to create real backend functionality. Build a command-line application and use files as simple storage to understand how backend systems manage data.

What Is Node.js?