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

I had to look too...

Google Lighthouse is an open-source, automated tool for measuring the quality of web pages. ... audits performance, accessibility, and search engine optimization factors of web pages

https://en.wikipedia.org/wiki/Google_Lighthouse

Hackernews: why are websites nowadays so bloated and slow??

Also hackernews: what's Lighthouse?

Sale here.

From https://developer.chrome.com/docs/lighthouse/overview/

> Lighthouse is an open-source, automated tool for improving the quality of web pages. [...] It has audits for performance, accessibility, progressive web apps, SEO, and more

It's shame it is ESM only package now for Node.js. Forces you to rewrite your tests to be able to use the latest version.

For that I would suggest something like this: https://www.npmjs.com/package/commonjs-to-es-module-codemod.

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

Thank you! Unfortunately seems like Falco's website is no more?

thanks for the excellent list!

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.

Unrelated, but you've followed me from Ozbargain!!! I don't have the same name, but you do!

haha, go the ozbargainers! :)

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.

You could work around this by having the Lighthouses run from a container pool.

Certainly. I entertained similar ideas, but I abandoned such notions because I was afraid it was circumventing rather than transcending the problem. I ended up concluding that if you're going to get this close to RUM you might as well just do it.

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!

I was going to mention CPU, too. I've noticed in the past that even for a single site (or web app, I guess I should say), it's possible to get somewhat a better Lighthouse score on a fast modern computer than on somethig that's a bit slower/older. I think it causes some devs to miss major performance issues.

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!