User Timings?

Hello Patrick,

I just noticed a new purple line on our private instance of WPT labeled ‘User Timings’. There also is a new metric being reported in the table that shows up for the median run labeled ‘User Time’. Is this sort of a ‘Time-to-interactive’ per se? How is this timing determined?



The User Timings API ( allows you to mark when you reach certain points on the page.

In your example above it looks like there’s a windoews.performance.mark call somewhere in the page.

+1 to Andy’s comment. Could be your code or being set by 3rd-party code that you include. If you hover over the triangle at the top of the waterfall it should hopefully tell you what the name of the event was.

That’s pretty sweet. So we literally could have multiple timings setup at various times during the page load for diagnostic/research purposes? The hover over function did work, in case you were wondering.


Works great for calibrating your synthetic and RUM data against each other as well. If you have multiple marks they should be called out individually and all visible (and also available in the API).

Thanks, I thought I had read something about this, but had not found it in the WPT forums. Nice to confirm that :slight_smile: