Web Vitals summit & performance.now() pre-event

Web Vitals summit & performance.now() pre-event

Before the performance.now() conference days started, I visited Google headquarters in Amsterdam and also gave a presentation on INP and the LoAF API during a performance meetup.

Web Vitals summit in Amsterdam

A Web Vitals summit was organized for Google Developer Experts and other experts involved with browsers and web performance.

Several topics were discussed:

  • Lighthouse vs CrUX;
  • the Interaction to Next Paint metric;
  • Browsers (and Firefox shipping Largest Contentful Paint);
  • And how to get others in the eco system on board with UX metrics.


Additionally, a pre-event was organized. Just like every other edition in prepara­tion for the actual performance.now() conference. Curious for a recap and all the slides of the talks and speakers? You can find it in this newer blogpost.

This year, the pre-event was sponsored by Speed Kit. And multple people were speaking about.. well, performance related topics. And I was one of them.

RUM & LoAF to fix INP

The subject of my talk might make sense. For starters because I'm the co-founder of a Real User Monitoring solution. At RUMvision, we have already implemented the new LoAF browser API, which is still a Chrome Origin Trial at time of writing.

And with the LoAF API, we were able to already collect valuable insights. Over at RUMvision, we have started to share findings with our clients already and we have been sharing insights with third party vendors as well. Which became the topic of my talk, to show the value of this new API.

The relation to INP is simple: the INP metric will become part of Core Web Vitals in March 2024. But it can be an intimidating metric. That is where this new LoAF API is coming in, helping anyone to get info on a higher level, although able to report way more than the long task API was able to do.

* November 7th update:

My presentation is now live on Youtube. Check it out:


The two links that can be found in the video: