gilbertococchi

performance.now(); 30th and 31st of October, Amsterdam On 30th and 31st of October, 2025, the sixth edition of performance.now() will take place in Amsterdam—a single track conference, covering today’s most important web performance insights.

performance.now(), the web performance conference, 30th and 31st of October, Amsterdam. Single track, the best speakers in the industry, plenty of your performance-mad peers around to have fascinating conversations. What's not to like? Let's introduce our speakers ...
perfnow.nl

The Chrome DevTools Performance panel just leveled up! 🚀 Here's a 69-second taste of the new hotness.

For some developers and/or framework authors I presume a notification could help understanding when a new feature is coming to land some experiment to send feedback and verify whether the feature suite their needs.

I think so, I personally subscribed to blink-dev because I am curious about when something starts to be available for experiment and be notified when something ships.

BFCache can hugely influence your page performance for URLs high on Back Forward Navigation types.

If you use CrUX or RUM and you see a lot of traffic in % attributed on Back Forward and few on BFCache maybe you are leaving money on the table!
CruXVis can help you measuring this opportunity!

Two lines of Cross-Document View Transitions code you can use on every website today Arguably, the most profound thing about the web is the ability to link one page to another.

The one where I muse about how this simple bit of code radically changes how the web itself seems to behave…

webkit.org/blog/16967/t...

GitHub - GoogleChrome/web-vitals: Essential metrics for a healthy site. Essential metrics for a healthy site. Contribute to GoogleChrome/web-vitals development by creating an account on GitHub.

We've just published v5.0.0 of the web-vitals JavaScript library for measuring Core Web Vitals.

github.com/GoogleChrome...

As a major release, this includes a number of breaking changes as detailed in the upgrading doc:

github.com/GoogleChrome...

Please read carefully before upgrading.

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Lighthouse is moving to performance insight audits  |  Blog  |  Chrome for Developers Lighthouse is moving to performance insight audits

We're updating Lighthouse to be based on the same Insights we recently launched in the Performance panel of Chrome DevTools.

developer.chrome.com/blog/moving-...

This will help align the tools but will be a breaking change. So we'll make that change in Lighthouse 13 in 6 months.

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WordPress 6.8 Field Guide This guide outlines major developer features and breaking changes in 6.8 and is published in the Release Candidate phase to help inform WordPress extending developers, Core developers, and others. …

WordPress 6.8 is out today. Including Speculation Rules in Core thanks ot some amazing work by @felixarntz.bsky.social !!
make.wordpress.org/core/2025/03...

It's a very conservative prefetch-on-mousedown default but site owners (or plugins) can customise that:
make.wordpress.org/core/2025/03...

FYI: developer.chrome.com/docs/css-ui/...

Alternatively, the CrUX History APIs are free and you can build your own dashboards as you see fit.

There are also LOTS of great CrUX tools out there — many with a free offering to view history such as Treo, Calibre...etc. So that's another option.

Episode 2 | PerformanceObserver - YouTube

🎥 The videos from our last meetup are now live on our YouTube channel! Here's the playlist:
www.youtube.com/playlist?lis...

Big thanks to @keerthanak17.bsky.social and @webx.bsky.social for speaking! ❤️

#webperf

In case you missed it cause you had better things to do on a Friday evening 🤷‍♂️, I wrote a detailed post on how to roll out speculation rules on more complex sites. Check it out.

Discover Ilaria Pierini’s Journey: From the Marche Region to a Sustainable Lifestyle - Lifestyle blog Discover Ilaria’s journey to a sustainable lifestyle, from vegan recipes to eco-friendly home tips. Get inspired by her story!

www.lifestylemind.com/healthy-life...

Yay! new CrUX API goodness! LCP Type and Image Subparts are now available!, so I've added them to my free CWV History Tool here: tamethebots.com/tools/cwv-hi...

Awesome #CrUX update by the people from #Google (and also partially available in our free tool as well) 👏

This was added:
→ LCP image subparts
→ LCP resource types
→ Round Trip Time (RTT) tri-bins
→ RTT p75 and histograms
We added #LCP resource type already as well (see attached).

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We don't have an official CrUX Bluesky account, so for the moment I'll announce the monthly releases. And we're starting with a big one!

🆕 The 202501 release is now live on BigQuery!

Check out the announcement post for the full info:
groups.google.com/a/chromium.o...

Highlights below 👇

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Making Baseline actionable with real user data  |  web.dev How RUMvision incorporated Baseline information with their RUM data.

Coolest thing ever🤩, our Baseline integration into RUMvision got featured as a use case web.dev/case-studies...

Not something I could have predicted when we started our startup 3 years ago, and was looking through web.dev as a source of info, which makes this even cooler! 🥳

RayBan managed to achieve 50% of CrUX counted Navigation Types accounted to Prerender Type on Desktop, that means that a lot of Ecommerce websites can benefit a lot from these innovations.
Especially if implemented in the PLP!

CrUX Vis CrUX Vis is an experiment by the Chrome team to help you explore the Chrome User Experiment Report data with visualizations and helpful links to articles, for a particular web page or origin.

Bonus: RayBan also unlocked BFCache and measure the impact of Prerender by using CrUX Navigation Types.
Take a look at the data by using cruxvis.withgoogle.com, if you see a high % of Back Forward Navigations and few that are bfcache perhaps you should focus some effort to unlock that potential!

How Ray-Ban doubled conversion rate and reduced exit rate by 13% through prerendering using the Speculation Rules API  |  web.dev Learn how Ray-Ban improved LCP by using the Speculation Rules API, and how it improved Ray-Ban's ecommerce platform's business performance.

Great to hear about new business stories being published about how leading firms such as #RayBan from Luxottica takes advantage of #SpeculationRules #Prerender on Chrome to double their conversion rate while improving LCP and other CWV metrics!

web.dev/case-studies...

Core Performance Team Rep nominations for 2025 This post kicks off the formal election process with a call for nominations for the 2025 Core Performance Team Reps. For about 2 years, Emily Clarke (@clarkeemily) and Felix Arntz (@flixos90) have …

With the start of 2025, the WordPress Core Performance Team is looking for 2 new Team Reps to represent the team as part of the broader project. If you want to nominate someone or volunteer yourself, don't hesitate and let us know in the post comments! 🙌

make.wordpress.org/performance/...

Congrats Sia!!!

Good luck with your new adventure Estela!

View Transitions Snippets: Getting all Animations linked to a View Transition A few lines of JavaScript to get all animations linked to an active View Transition.

View Transitions Snippets: Getting all Animations linked to a View Transition

🔗 brm.us/view-transit...
🏷️ #ViewTransitions #JavaScript #Animations

Sorry to hear that Barry.

So even if Chrome is supporting BFCache on some situations, it would still be good to check again your site Cache-Control: no-store usage to see if that's really necessary to keep.

It's insightful how some sites built with some technologies are more prone to use this header value vs others...

Sorry, I meant to say "Cache-Control: no-store".

Chrome is ramping up CCNS support on BFCache but the logic would impact limited conditions and other API usage will continue to keep the page BFCache ineligilbe.
developer.chrome.com/docs/web-pla...