Now I only need to know what Lighthouse does to figure out what this does.

nice! my running list of other similar tools: https://www.swyx.io/webperf-tests

Very impressed. Nice UI/UX as well. However, get the occasional "Required traces gatherer did not run", without any explanation as to why/what that infers. A [search] didn't turn up anything particularly obvious.

What does opportunistic threading mean here? I’d have to dig up the issue, but I attempted something like this once and discovered that it’s discouraged if not forbidden to run more than one lighthouse instance at a time. If I recall correctly it has/had something to do with a lock on a certain tmp directory and a need/desire for accurate CPU profiling.

Am I crazy? Does this sound familiar to anyone? Apologies I can’t investigate deeper at the moment. I’m on mobile and will have to circle back later.

Reminds me, I had to once set up lighthouse scans for thousands of sites and the only way to do this fast enough was to run the tests concurrently on a single machine. But the test results also depended on cpu load of thr machine running the tests, so we had to sample cpu load live and adjust a multiplier in the lighthouse tests to handle this so that lighthouse would not think it is the site that is being slow. I understand it’s a complex tool, but I wish lighthouse results with the cli were more reproducible!

Chances are this post was inspired from Fireship's latest video - https://youtu.be/0fONene3OIA on his second channel. It is worth checking out. Amazing tool for SEO optimization and other use cases to improve web performance

Very nice. We have a very primitive tool for this at the moment, might look at moving to this.

Awesome, thanks!