performance.now() conference

Three new speakers were announced for perfnow.nl ! Aleth Gueguen about native web and PWAs. @adactio.com about long-term performance: not milliseconds but decades Risko Ruus about regression testing and other QA Tickets: perfnow.nl/tickets.html See you in November in Amsterdam!

​​Designers see performance as a constraint, or as a checklist item: “don’t forget the spinner.” What if we saw it as a design opportunity instead? In November, I'll explore what developers should expect from their designers and how to ask for it at @perfnow.nl in Amsterdam. perfnow.nl/

The number of connection address and protocol combinations keeps growing, and every browser behaves differently. With Happy Eyeballs v3 browsers will fall back to a working option faster and more safely. This session will show what its performance impact looks like. Max Inden at perfnow.nl

Sometimes custom solutions that we build highlight deeper challenges with performance and usability, and reveal an opportunity to grow the web’s native capabilities. How doe you move from patterns that work on one website to features that are built into our browsers? @scottjehl.com at perfnow.nl

With 2 years of rollouts, we've learned a lot about compression dictionaries and the Web. Patrick will cover what works, where the footguns are, how to maximize their effectiveness, and other experiments around compressing content on the web. @patmeenan.com at perfnow.nl

In this deep-dive session, Tim will use real-world data and performance metrics to show how scalemates.com became the fastest and largest scale modelling website in the world. You’ll leave with practical, actionable insights to push performance even further. @timvereecke.bsky.social at perfnow.nl

The provisional SCHEDULE is live; changes still possible. perfnow.nl/schedule.html

Small changes can mean death by a thousand cuts for your performance. This talk is about what Risko learned about regressions, where the numbers lied, unrealistic throttling, and why "LCP doubled" isn't always bad news. You'll leave with a tester's view of web performance. Risko Ruus at perfnow.nl

What if we could provide websites that have the ability to do their thing while being offline? In this talk, I’ll show you how I’ve harnessed the native web APIs to implement offline capabilities while minimizing the amount of Javascript to execute in the browser. Aleth Gueguen at perfnow.nl

Getting web performance prioritized is the hard part. I will talk about this topic on @perfnow.nl. How do you make the case for web performance? → Share your experience in this 3–5-minute survey: pagespeed.one/en/perfnow 🙏 #WebPerf #WebPerformance #PageSpeed

Designers see performance as a constraint, or as a checklist item: “don’t forget the spinner.” What if we saw it as a design opportunity instead? This talk explores what developers should expect from their designers and how to ask for it. @stephaniewalter.bsky.social at perfnow.nl

Mobile Core Web Vitals are being built with real user data, and are tied to both business impact and a specific fix. But a lot doesn't transfer from the web: LC assumes a page load, CLS a document. This talk shares the first public look at Mobile CWV. @cliffcrocker.bsky.social at perfnow.nl

Why is speed so hard to sell? Martin will look at where familiar arguments fail, what WebPerf can learn from SEO, and why ownership and incentives matter as much as metrics. You will leave with practical tips to turn performance into prioritized work. @machal.bsky.social at perfnow.nl

If we look at a few decades of web performance, what technologies and techniques worked, what didn’t, what made the most difference, what has stood the test of time? Making a fast website is challenging enough; keeping a website fast is harder! @adactio.com at perfnow.nl

Reminder: tickets get more expensive onThursday. There are only nine tickets in the middle bracket left. perfnow.nl/tickets.html

Reminder: ticket prices will go up by €100 + VAT this Wednesday, 1st of July. There are a few cheap tickets left. We also announced @patmeenan.com, @stephaniewalter.bsky.social and @programmingart.bsky.social (MC). perfnow.nl/tickets.html

Remember: ticket prices will go up by €100 + VAT next Wednesday, 1st of July. Grab your cheap tickets while you can. perfnow.nl/tickets.html

My presentation, Making Performance Allies from @perfnow.nl just got posted to YouTube - www.youtube.com/watch?v=ygdx.... The tips I share in the presentation were designed to make #webperf stick beyond the occasional task that finds its way out of the backlog. Enjoy!

My talk from @perfnow.nl is out! It was a super special time compiling years of information on Accessibility and Performance into one talk. Even cooler that my little family could be there in Amsterdam to see it. 💗 youtu.be/Fdvk_qOKjVM?... #a11y

Six early-bird tickets left. Will they run out today? Or are you feeling lucky and wait for Monday? perfnow.nl/tickets.html

Ticket acquired. Can’t wait to see you all later this year! Go get yours!

Ticket sales are open! perfnow.nl/tickets.html

We just sent out a TEST MAIL to our mailing list. Last year quite a few people didn't see the announcement mail and missed the early bird ticket sale. So this year we run a test first. If you're subscribed to our mailing list, please make sure you got the test mail. Or perfnow.nl/subscribe

performance.now() 2026 is coming. Ticket sales will open in May with cheap and ultra-cheap early bird tickets. These will be announced in our newsletter first. So subscribe via perfnow.nl/subscribe perfnow.nl

performance.now() 2026 is coming. Ticket sales will open in May with cheap and ultra-cheap early bird tickets. These will be announced in our newsletter first. So subscribe via perfnow.nl/subscribe perfnow.nl

Conference organising in 2026 quirksmode.org/quirksblog/a...

2025 conference photos are up perfnow.nl/2025/pix/pho... (though I need to consult a speculation rules expert at some point)

And the performance.sync() videos, the Wednesday pre-party, are also live. www.youtube.com/@WebConferen...

Team photos are up. perfnow.nl/teams-2025.h...

A little aftermovie to whet your appetite. www.youtube.com/watch?v=ByOC...

Here you go! My first perf now as a speaker… it’s was amazing 🤩 docs.google.com/presentation...

I shilled a javascript framework at a web perf conference and came out mostly unscathed, AMA

performance.now() 2026 will take place on 19th and 20th of November 2026. #perfnow.

Unsurprising revelation from #perfnow: @rich-harris.dev really is ruddy good at demonstrating interesting concepts. His @svelte.dev is demo is terribly compelling.

"Family. The #webperf community is family." - Dom Toretto @rich-harris.dev #PerfNow

@rich-harris.dev might have the best demo app I have ever seen 😁 at #perfNow

"SSR is about ~SEO~ performance" - @rich-harris.dev #perfnow #WebPerf

#perfnow absolutely fantastic and compelling demos from @rich-harris.dev but I'm trying to resist concerns on his preference for tabs over spaces...😂

@perfnow.nl for whoever asked that question about Sec-Purpose it DOES get set on sub-resources for prerendered speculations. Not just the document. #perfnow

It’s an honor to see my company #speedkit mentioned on stage at #perfnow by a web performance VIP and ambassador such as Barry @tunetheweb.com Pollard. 😊 Congrats to the Speed Kit team who implemented speculation rules in such an effective way in our product!

Making Sense of Long Animation Frames… The slides from my #PerfNow talk are available on Notist noti.st/andydavies/9...

Here are mine: speakerdeck.com/ethangardner...

speakerdeck.com/csswizardry/...

Interesting! Etsy implemented speculation rules and got these results: 👍 Time to First Byte on the listing page improved 23.6% 👍 First Contentful Paint improved 20.7% 👍 Largest Contentful Paint improved 21.1% 👍 DOMContentLoaded improved 20.4% #PerfNow #webperf www.etsy.com/codeascraft/...

#PerfNow has incredibly interesting talks. Anyone who's serious about performance should join. Proud that we at @framer.com are sponsors.

Here are mine! Thanks for a wonderful conference 🫶🏻 bit.ly/a11y-perfnow25

Always, always happy to see @yoav.ws get a shout-out. So much incredible work has happened because of him. Most recent example—speculation rules in WebKit. #perfnow

Super talk from @tunetheweb.com on Speculation Rules. Been nervous about using them for fear of false positives on things like Google Analytics. The upcoming prerender_until_script logic sounds like exactly what I need - you'll benefit from fetching subresources, but won't execute scripts. #PerfNow