I was curious to see where Server-Timing was implemented on the web, so I started searching the HTTP Archive for sites using it. Interestingly enough, there were no sites in the HTTP Archive that had Server-Timing response headers before 3/1/2017. Since then it’s usage has been gradually increasing each month. As of July 2017, there are 72 sites and 352 HTTP responses containing Server-Timing headers.

I worked on an interesting performance investigation recently, and I wanted to share some of the techniques I used to dig in and isolate the problem.