What is express-status-monitor?

express-status-monitor is a Node.js module that adds a real-time metrics dashboard to any Express web application. Express is the most widely used web framework for Node.js, and this module plugs into it as middleware, a piece of code that processes requests before they reach your application's main logic. Once added, the module makes a status page available at the /status route of your server. The page displays live charts showing how the server is performing: CPU usage, memory consumption, heap size, event loop lag, average response time, requests per second, and a breakdown of HTTP status codes returned by the server. The dashboard updates in real time using Socket.io, a library for pushing data from the server to the browser continuously as it changes. The charts are rendered using Chart.js. Both are bundled into the module, so no additional front-end setup is required. Configuration is optional. By default, the module collects data at three intervals (every 1, 5, and 15 seconds) and keeps 60 data points for each, giving you a sliding window of recent activity. You can customize which charts appear, the path where the status page is served, and which URL prefixes to exclude from monitoring. Health checks can be added to the configuration. These are URLs that the module periodically pings. If an endpoint returns a 200 status code, the check is marked as healthy. The results appear on the status page alongside the performance metrics. The status page can be protected with authentication middleware of your choice, since the page handler is exposed as a separate property that can be wrapped independently. Installation requires adding one line to your Express application. The module requires Node.js version 4 or higher and is MIT licensed.