Node.js is an open-source, cross-platform runtime environment that allows developers to run JavaScript on the server side. It is built on Google Chrome’s V8 JavaScript engine and is designed to build fast and scalable network applications.

Unlike traditional JavaScript, which runs only in the browser, Node.js enables developers to use JavaScript for backend development. This means you can build both frontend and backend applications using the same language.

Node.js is known for its:

• Non-blocking, event-driven architecture
• High performance and scalability
• Ability to handle multiple requests simultaneously
• Strong ecosystem with npm (Node Package Manager)

It is commonly used for:

• Building REST APIs
• Real-time applications (like chat apps)
• Streaming applications
• Microservices
• Full-stack development

Node.js is widely used in modern web development because it is fast, efficient, and ideal for data-intensive and real-time applications.