PM2 vs nodemon: What are the differences?

In the world of Node.js development, developers often use tools like PM2 and nodemon to enhance their development experience. Let's explore the key differences between them.

1. Auto-restart vs. Process Management: PM2 focuses on process management, providing features like load balancing, clustering, and zero-downtime deployments. It can run multiple instances of an application and restart them when necessary. On the other hand, nodemon is primarily designed for auto-restarting a Node.js application whenever a file change is detected. It is more suitable for local development and does not offer process management capabilities.

2. Configuration and Command-line Options: PM2 offers a wide range of configuration options and command-line parameters to fine-tune the behavior of the managed processes. It allows customization of log outputs, environment variables, and advanced features like watch mode and hot-reloading. Nodemon, on the other hand, has a simpler configuration approach that relies on a configuration file or command-line arguments.

3. Monitoring and Logging: PM2 provides a built-in monitoring dashboard that displays real-time information about the running processes, CPU usage, memory consumption, and more. It also offers log management features, allowing developers to stream and rotate log files. Nodemon, however, does not have built-in monitoring or log management capabilities.

4. Compatibility with Cluster Mode: PM2 supports clustering out of the box, allowing developers to leverage the full power of multiple CPU cores by spawning multiple instances of their application. Nodemon, on the other hand, is not designed to work in a clustered environment.

5. Integration with Process Management Tools: PM2 integrates well with process management tools like systemd or Windows service managers, enabling developers to run their Node.js applications as background services. Nodemon, being focused on local development, does not provide built-in integration with such tools.

6. Community and Ecosystem: PM2 has a large and active community, with a rich ecosystem of plugins, monitoring tools, and third-party integrations. It is widely used and has been battle-tested in production environments. While nodemon also has a decent community, it may not offer as many options for extending its functionalities or integrating with other tools compared to PM2.

In summary, While both PM2 and nodemon aid in Node.js development, PM2 is primarily used in production environments to manage Node.js processes and ensure application stability and scalability, whereas nodemon is favored during development for its ability to automatically reload the server and speed up the development process.