Node.js is an open-source, cross-platform JavaScript runtime that enables server-side JavaScript execution. It is built on a non-blocking, event-driven architecture, allowing it to efficiently handle multiple tasks concurrently. Node.js uses a single-threaded event loop to process asynchronous operations, making it ideal for scalable real-time applications, web servers, and APIs.
While it offers the advantage of using JavaScript for both client and server-side development and has a vast ecosystem via NPM, it faces challenges. Its single-threaded nature can struggle with CPU-intensive tasks, and scalability across multiple cores requires additional effort.