iiinova — where your digital self keeps evolving

Reposted by Tim Vereecke

performance.now() conference @perfnow.nl · 22/09/2026

Oh dear, speakers are being announced in carload lots! Today we add bsky.app/profile/clif... about Core Mobile Vitals bsky.app/profile/jpam... as our second MC bsky.app/profile/mach... about selling web performance Come join them at perfnow.nl

perfnow.nl

performance.now(); 19th and 20th of November 2026, Amsterdam

On 19th and 20th of November 2026, the web performance community will gather at performance.now() in Amsterdam to discuss today’s most important web performance insights.

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Tim Vereecke @timvereecke.bsky.social · 10/09/2026

I really wish caniuse.com showed browser-specific usage percentages too. “1.28% of global users don’t support this” sounds insignificant. “9.6% of Safari users don’t support this” tells a very different story. Global usage can hide some pretty important details.

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Tim Vereecke @timvereecke.bsky.social · 27/05/2026

nice indeed! I do miss prerender as a navigation type

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Tim Vereecke @timvereecke.bsky.social · 18/05/2026

This mPulse graph shows image requests per page. Before the rollout, the blue line (prerendered) requested more images than the non-prerendered. After the fix, the two lines converged. Result: lower bandwidth usage, and the ability to prerender pages more aggressively. #webperf

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Tim Vereecke @timvereecke.bsky.social · 18/05/2026

While I’m a big fan of the Speculation Rules API, there used to be one major downside: prerendered pages ignored loading=lazy, causing all images to download. That changed 2 months ago.

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Tim Vereecke @timvereecke.bsky.social · 12/05/2026

New speed record 🚀 Just measured a 15ms Largest Contentful Paint (LCP), the fastest (prerendered) navigation I’ve seen so far on my website using RUM. #webperf

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Tim Vereecke @timvereecke.bsky.social · 20/02/2026

Documentation: techdocs.akamai.com/property-mgr...

techdocs.akamai.com

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Tim Vereecke @timvereecke.bsky.social · 20/02/2026

Sometimes, legacy applications use POST instead of GET to retrieve data. On Akamai, you can easily force caching of specific POST responses to improve both offload and performance. In the screenshot below, you can see the first (slow) and subsequent data retrievals using POST (fast, cached).

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Reposted by Tim Vereecke

Barry Pollard @tunetheweb.com · 04/02/2026

From Chrome 145 (on general release next week!), DevTools we will start to show so called "soft" navigations and "Soft LCP" in the Performance Panel traces. These are for SPAs which don't do a full page load, but instead "fake it" by updating the current page and pushing a new history entry. 1/5 🧵

Screenshot of a performance trace in Chrome DevTools with a few additional "Nav*" and "LCP*" markers. Hovering over the "LCP*" shows this is a "Soft LCP" and in the Summary panel when you click on it you see "Soft Largest Contentful Paint" and a "Learn more about Soft Largest Contentful Paint" link.

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Tim Vereecke @timvereecke.bsky.social · 23/01/2026

I registered for the origin trial and it works as expected. I no longer see any JS based changes or requests when using prerender_until_script. thx!

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Reposted by Tim Vereecke

Barry Pollard @tunetheweb.com · 23/01/2026

Think prefetch is not enough, but prerender is too risky for your site? Well then check out "prerender until script"—a new option we're testing for the Speculation Rules API now available for you to test on your site with an origin trial! developer.chrome.com/blog/prerend...

developer.chrome.com

Speculation rules prerender until script origin trial | Blog | Chrome for Developers

Learn about the new prerender until script option for the Speculation Rules API, now available in origin trial.

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Tim Vereecke @timvereecke.bsky.social · 19/01/2026

Jquery 4.0.0 is out, great byte savings in the latest release #webperf

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Reposted by Tim Vereecke

Barry Pollard @tunetheweb.com · 09/12/2025

🆕 The 202511 Chrome User Experience (CrUX) release is now live on BigQuery! Check out the announcement post for the full info: groups.google.com/a/chromium.o... Highlights below 👇 🧵 1/3

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Tim Vereecke @timvereecke.bsky.social · 28/11/2025

@searchliaison.bsky.social I spotted this on 2 different sites and 2 different CDN's. Is this a common pattern or is it linked to individual sites?

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Tim Vereecke @timvereecke.bsky.social · 28/11/2025

Anyone else seeing a degradation of Average Download time (+90ms ish) in Google Crawl Stats that started on(Around) September 24th? #webperf #crawler

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Tim Vereecke @timvereecke.bsky.social · 07/11/2025

thx Michal! it was a great presentation

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Tim Vereecke @timvereecke.bsky.social · 07/11/2025

The new SVG hack? (Context: The lack of preconnect/preload means there is 0.000 performance impact for the user) Gaming the system? Lack of knowledge? Or is there a benefit not linked to #webperf? Heard about this at @perfnow.nl

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Tim Vereecke @timvereecke.bsky.social · 05/11/2025

103 Early Hints is now supported by more than 92% of all users. When done right, it is a great way to improve your higher percentiles of FCP and LCP #webperf

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Tim Vereecke @timvereecke.bsky.social · 31/10/2025

That was Desktop only! above is for ”all”

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Tim Vereecke @timvereecke.bsky.social · 31/10/2025

Scalemates was used by @tunetheweb.com as an example of how fast a site can be using the Speculation Rules API. It has an LCP of 483ms at the P75! #webperf

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Reposted by Tim Vereecke

Tim Vereecke @timvereecke.bsky.social · 15/01/2025

Why is my site fast? 55% of my pageviews on Desktop are coming from Bfbache or had an early start with Prerendering. 👌 #webperf is easy* in 2025 (*I know I know)

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Tim Vereecke @timvereecke.bsky.social · 15/01/2025

Why is my site fast? 55% of my pageviews on Desktop are coming from Bfbache or had an early start with Prerendering. 👌 #webperf is easy* in 2025 (*I know I know)

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Tim Vereecke @timvereecke.bsky.social · 10/01/2025

Amazing (and simple) technique by @kilianvalkhof.com . autofocus is a great way to make your login/registration and password reset forms more user-friendly htmhell.dev/adventcalend... I implemented it during my lunch break... so much better! #UX #htmhell

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Reposted by Tim Vereecke

Tony McCreath @tony.mccreath.id.au · 09/01/2025

Great stuff. I just watched a talk from @timvereecke.bsky.social that covered the redirects, and I was surprised how big an impact they can have on TTFB. Time to track redirects in my RUM data (when possible). youtu.be/E2E89NeBbEM?...

youtu.be

Tim Vereecke at performance.sync()

YouTube video by Web Conferences Amsterdam

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Tim Vereecke @timvereecke.bsky.social · 09/01/2025

They should invent a CLS score for slide decks! #webperf #presentations

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Tim Vereecke @timvereecke.bsky.social · 08/01/2025

Excellent! Much needed improvement

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Patrick Meenan @patmeenan.com · 06/01/2025

Hmm, interesting - looks like Chrome added support for the ORIGIN frame for HTTP/3 (eliminating the need for a DNS lookup before coalescing connections). blog.chromium.org/2024/12/maki...

blog.chromium.org

Making Chrome QUICer

In October 2020, Chrome enabled HTTP/3 by default . HTTP/3 ( RFC 9114 ) runs over IETF QUIC ( RFC9000 ). Default-enabling HTTP/3 in Chrome ...

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Tim Vereecke @timvereecke.bsky.social · 06/01/2025

Have you ever noticed unexplainable performance degradations? Unattributed Navigation Overhead (UNO) is probably the missing link. Watch my Lightning Talk from the performance.sync() meetup in Amsterdam! #webperf #rum #ttfb #cwv www.youtube.com/watch?v=E2E8...

youtube.com

Tim Vereecke at performance.sync()

YouTube video by Web Conferences Amsterdam

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Tim Vereecke @timvereecke.bsky.social · 02/01/2025

Amazing article! Will instantly apply it to my facetted navigation with sometimes 1000+ iterations, one for each filter

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Reposted by Tim Vereecke

Vinicius Dallacqua @webx.bsky.social · 22/12/2024

This article is such a gem! And the talk at Performance.sync() was too: youtu.be/E2E89NeBbEM?...

youtu.be

Tim Vereecke at performance.sync()

YouTube video by Web Conferences Amsterdam

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Reposted by Tim Vereecke

Stoyan Stefanov @stoyan.me · 21/12/2024

Web performance calendar day 21 with @timvereecke.bsky.social giving us the gift of UNO (Unattributed Navigation Overhead) - an insight into the blind spot gaps between TTFB components calendar.perfplanet.com/2024/uno/

calendar.perfplanet.com

Unattributed Navigation Overhead (UNO)

I promise you, UNO (Unattributed Navigation Overhead) is the best Christmas present you will get this year! UNO, not the card game, is the missing piece for many of your unsolved performance puzzles...

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Reposted by Tim Vereecke

Peter Mbanugo @pmbanugo.me · 09/12/2024

Ready to make your sites load like 🚀? Join our latest livestream with @timvereecke.bsky.social where we dive deep into the Speculation Rules API! 🎥 What’s in it: - Pre-rendering & Prefetching Magic - Real-World Use Cases - Simple to complex use-case Catch the action on YouTube: dub.sh/MyXjkeC

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Tim Vereecke @timvereecke.bsky.social · 04/12/2024

You want a score that improves/degrades. If you just use (min) you could go from (95, 97, 72) to (76, 78, 73) and be happy you “improved”

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Aleksey Kulikov @alekseykulikov.bsky.social · 03/12/2024

Here's my idea for Vital Score: • shows % of traffic passing CWVs • no weights, shows the progress, easy to compare, evolves CWV assessment • formula: (LCP+CLS+INP+ min(LCP, CLS, INP)) / 4 What do you think? #webperf Thx @timvereecke.bsky.social for min() trick and @csswizardry.com for CrRRUX

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Paul Calvano @paulcalvano.bsky.social · 03/12/2024

This Friday afternoon I'll be at the Boston Web Performance meetup giving my talk on "Performance Mistakes". If you are in the Boston area and interested in web performance, join us! www.meetup.com/boston-web-p...

meetup.com

Performance Mistakes, Fri, Dec 6, 2024, 4:30 PM | Meetup

December's meetup will feature Paul Calvano, on his return from the PerfNow conference in Amsterdam. **Agenda** * 4:30 pm: Arrive & networking * 5:00 pm: Talk starts * 5:

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Tim Vereecke @timvereecke.bsky.social · 28/11/2024

The new mPulse widgets with attributions for LCP, CLS and INP have made my performance checks more efficient and effective! #rum #cwv

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Tim Vereecke @timvereecke.bsky.social · 27/11/2024

My #wls2024 talk is available! I delved into advanced tuning techniques to make a modern website lightning fast. Using lots of charts and data, I showed how they helped make scalemates the fastest (and largest) modeling website in the world. www.youtube.com/watch?v=rjUr... #webperf

youtube.com

Beyond the basics, pushing the limits of webperf — Tim Vereecke

YouTube video by We Love Speed

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Tim Vereecke @timvereecke.bsky.social · 26/11/2024

Great talk Robin! Is there a way in RUM to detect when Tight mode ends?

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Robin Marx @programmingart.bsky.social · 26/11/2024

My talk from this year's We Love Speed is on YouTube! 👇 In "Tight Mode: how browsers REALLY load web pages", I take a very deep/very nerdy dive into why browsers sometimes intentionally delay loading resources, why they all do it differently, and why they should *stop clowning around* 🤡 #webperf

youtube.com

How browsers REALLY load Web pages — Robin Marx

YouTube video by We Love Speed

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Reposted by Tim Vereecke

Kevin Farrugia @imkev.dev · 26/11/2024

Super interesting talk on advanced performance techniques from @timvereecke.bsky.social for #welovespeed. 🙌 www.youtube.com/watch?v=rjUr...

youtube.com

Beyond the basics, pushing the limits of webperf — Tim Vereecke

YouTube video by We Love Speed

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Tim Vereecke @timvereecke.bsky.social · 25/11/2024

The simplest view transitions example is a bit boring after a while! Something more fancy is complex! "auto" should ideally show different transitions based on the directory of the "old" vs "new" - /a/ » /a/b/ - /a/b/ » /b/ - /a/1.html » /a/2.html - /a/b/3.html » /d/e/f/4.html @bram.us

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