Node.js is a powerful JavaScript runtime built on Chrome's V8 JavaScript engine. It allows you to run JavaScript outside of a browser. Below are some common categories and use cases for Node.js:
- Web Development: Node.js is widely used for building scalable web applications. It provides a non-blocking, event-driven architecture, making it efficient for handling concurrent connections.
- API Development: Node.js is excellent for creating RESTful APIs and microservices due to its lightweight nature and high performance.
- Command Line Tools: You can use Node.js to create command-line tools that automate tasks and improve productivity.
- IoT (Internet of Things): Node.js is suitable for IoT applications due to its ability to handle real-time data and its efficient resource usage.
Here are some popular Node.js frameworks:
- Express: A minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.
- Koa: An asynchronous, Express-like web framework that focuses on simplicity and scalability.
- NestJS: A progressive Node.js framework for building efficient, scalable, and maintainable web applications.

For more information on Node.js, you can visit the official Node.js website.