Pm2 is an advanced, production process manager for Node.js applications that allows developers to keep their apps alive and maintain optimal performance. It helps you to keep an eye on your apps and make sure they are running smoothly and efficiently. With pm2, you can monitor your applications in real-time and restart them automatically if any errors occur. Plus, you can also configure it to automatically scale your application based on the number of requests that it receives. This makes it an invaluable tool for any developer looking to ensure their applications are running optimally and securely.