The following diagram provides an overview of how Node.js is structured:

The APIs available to a Node.js app consist of:

• The ECMAScript standard library (which is part of the language)

• Node.js APIs (which are not part of the language proper):

  • Some of the APIs are provided via global variables:

    • Especially cross-platform web APIs such as fetch and CompressionStream fall into this category.

    • But a few Node.js-only APIs are global, too – for example, process.

  • The remaining Node.js APIs are provided via built-in modules – for example, 'node:path' (functions and constants for handling file system paths) and 'node:fs' (functionality related to the file system).