@erwinhofman.bsky.social

Google Developer Expert in web performance CTO @ RUMvision.com Also sharing over at https://linkedin.com/in/erwinhofman

For the web dev nerds: meet `containertiming`! That's right, just an attribute! 🧵👇 You might have heard of elementtiming (and maybe also Server-Timing, performance mark/measure etc) already. `elementtiming` can be used for tracking image and text nodes (p, h1 etc) paint timings. 1/6

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Yes, I know it's Friday… but I deployed this anyway! 😎 We added the No-Vary-Search response header to a bunch of sites to ignore tracking parameters like `utm_*`, `gclid`, and `fbclid`. They’re consumed by third party tracking scripts, but they should not create .. 1/4

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A fix is already here! That's fast 🚀 Thank you @webkitgtk.org Team! Hopefully already there in next Safari release 🤓 bugs.webkit.org/show_bug.cgi...

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@erwinhofman.bsky.social · 6mo ago

With #CoreWebVitals data, we usually help agencies and merchants improve their sites and shops. But sometimes the data helps browsers too. An example: We recently spotted very inflated INP numbers across many sites on mobile (P75) specifically for `back-forward-cache` aka #BFcache navigations. 1/5

With #CoreWebVitals data, we usually help agencies and merchants improve their sites and shops. But sometimes the data helps browsers too. An example: We recently spotted very inflated INP numbers across many sites on mobile (P75) specifically for `back-forward-cache` aka #BFcache navigations. 1/5

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Using`preventDefault` within <dialog> close event causes mobile Chrome (but not Brave) to crash 😬 ``` document.body.addEventListener('command', (e) => { if (e.command === 'close') { e.preventDefault(); } }, { capture: true } ) ``` (crashing on v143 & 144 @ Android 13 & 16)

(literally) breaking update: Is your site using #Facebook, like many others? Our RUM data shows it's breaking the #UX of.. all of them! According to our data of all our #RUM users, Facebook shipped an update on Dec 8th at 18:15 UTC. They started using the `unload` event again 😬 1/6

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Look at that 🤩 Safari now supports #LCP and #INP as well! And we can clearly see it in our data 💪 Dates: 🗓️ Nov 3rd: Safari rolled out support in their 26.2 beta release 🗓️ Dec 12th: Safari released it to the public Huge update from the WebKit team, and for #CoreWebVitals in general 👏 1/3

Chart of INP + LCP metrics in Safari over time

Weekend! But also: looking back at quite the event, venue and community! I’ve only spoken to a purely #SEO audience a handful of times, but this one was truly energizing! A stable internet was needed to pull off the live quiz. Some attendees couldn’t even join in 😬 1/4

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New speaking gig confirmed: #SEOBenelux 🤟 Happening next week in between my 2 other scheduled talks this month! But this edition and talk will be different: → pure #SEO audience → bringing me back at another SEO event → this time in #Antwerp, October 10th 1/2

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We just added something nerdy to our tool, as treemaps seems to be hot in #JavaScript + web #performance world 🔥 When using RUMvision - Core Web Vitals monitoring to track #UX in real-time, we already show site owners a third party dashboard. But we now added a treemap-view as well: 1/4

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