PerfMap – A Front-end Performance Heatmap

PerfMap is a front-end performance heatmap. It’s a bookmarklet to create a front-end performance heatmap of resources loaded in the browser using the Resource Timing API. A browser with support for the Resource Timing API is required.

The heatmap colours and the first ms value indicate at what point in the page load the image finished loading. It’s a good indicator of user experience… “It took 3450ms before the user saw this image.” The second value in brackets is the time it took the browser to load that specific image.

Requirements: JavaScript Bookmarklet
Demo: https://github.com/zeman/perfmap
License: License Free