What Node.js is, and the role of V8

Model answer. Node.js is neither a language nor a framework: it is a runtime environment that runs JavaScript outside the browser, typically on servers and in command-line tools.

It combines:

• V8, Google's JavaScript engine (also used in Chrome), which compiles and executes the JavaScript itself.
• libuv, a C library that provides the event loop, asynchronous file and network I/O, and a small thread pool.
• Built-in modules such as fs, http, path, crypto, stream and events.

What it does not have: the browser's window, document and DOM. A browser and Node run the same language with different host APIs.

Frameworks such as Express, NestJS and Fastify are libraries built on top of Node to make writing web servers easier, the same way Django sits on top of Python.