Find out how long it takes to load a specific resource, such as an XMLHttpRequest, SVG, image, or script.

Find out what kind of internet connection your website visitor is using - celluar, wifi, etc. This can be used to select high definition content or low definition content based on the user's connection.

The Navigation Timing API provides data that can be used to measure the performance of a web site, including how quickly or slowly something loads.

Find out what tasks on your page, including style changes or events in your JavaScript, take 50 milliseconds or more.