NPM (short for Node Package Manager) is a package manager for JavaScript that is used to manage software dependencies and libraries for Node.js-based projects. It is the default package manager for Node.js and is bundled with it. NPM allows developers to easily download and install pre-written code packages (called "packages" or "modules") from a central repository, which can be used to extend the functionality of their projects. NPM provides a command-line interface (CLI) that makes it easy to search for, install, and manage packages. It also allows developers to publish and share their own packages with the wider community. NPM has become an essential tool for modern JavaScript developers, especially those building applications and projects using Node.js.