mod_telemetry keeps track of all URLs on your site and how long it takes your server to deliver each request. It reports these by using a status handler (like /server-status) to display real-time status information about the performance of your site.

It is extremely useful in optimizing back-end processes (for example, when connecting to Java, FastCGI, or Ruby back-ends) to identify when specific pages are performing slowly.

Because it runs in the server, it's able to show end-to-end performance on each request

It requires that mod_status be enabled to work.