CrUX.RUN

Global performance insights for your site | Lighthouse Metrics

I hadn’t come across this before—run Lighthouse tests on your pages from six different locations around the world at once.

The Core Web Vitals hype train

Goodhart’s Law applied to Google’s core web vitals:

If developers start to focus solely on Core Web Vitals because it is important for SEO, then some folks will undoubtedly try to game the system.

Personally, my beef with core web vitals is that they introduce even more uneccessary initialisms (see, for example, Harry’s recent post where he uses CWV metrics like LCP, FID, and CLS—alongside TTFB and SI—to look at PLPs, PDPs, and SRPs. I mean, WTF?).

Is my host fast yet?

This is an interesting project to try to rank web hosts by performance:

Real-world server response (Time to First Byte) latencies, as experienced by real-world users navigating the web.

Web bloat

Pages are often designed so that they’re hard or impossible to read if some dependency fails to load. On a slow connection, it’s quite common for at least one depedency to fail.

Fire up Reader Mode and read this excellent article informed by data from using a typically slow connection in rural USA today. Two findings are:

1. A large fraction of the web is unusable on a bad connection. Even on a good (0% packetloss, no ping spike) dialup connection, some sites won’t load.
2. Some sites will use a lot of data!

Why it’s tricky to measure Server-side Rendering performance

A good analysis, but my takeaway was that the article could equally be called Why it’s tricky to measure Client-side Rendering performance. In a nutshell, just looking at metrics can be misleading.

Pre-classified metrics are a good signal for measuring performance. At the end of the day though, they may not properly reflect your site’s performance story. Profile each possibility and give it the eye test.

And it’s always worth bearing this in mind:

The best way to prioritize content by building a static site. Ask yourself if the content needs JavaScript.