Node.js is a fast, event-driven JavaScript runtime that enables efficient server-side development. Ideal for building real-time, scalable, and high-performance applications, Node.js is widely used for APIs, microservices, and full-stack web development. Its non-blocking I/O and single-threaded architecture make it perfect for handling concurrent connections with ease. With vast NPM packages and strong community support, Node.js accelerates modern web application development.