Case studies: the benefits of optimizing Core Web Vitals
There's a big correlation between the Core Web Vitals and UX metrics. This article highlights the impact that optimizing Core Web Vitals had on major businesses worldwide.
Pagespeed findings
Slides Fronteers 2025
Frontend developement conference in Dordrecht
Ciao Rome! Meet Magento Italy 2025 slides
All roads lead to Rome, but it was our first time giving a talk in Italy. And it was a great succes! Want to find the slides, read about our Baseline integration, the Zitmaxx use case or how to improve webperformance for Hyvä, you find al the resources here.
Interop 2026: Key APIs for sitespeed & RUM
At RUMvision, our focus is helping site owners make their sites faster. To do that well, we depend on the data browsers give us through APIs. Some of those APIs are already incredibly useful — but not all browsers support them consistently.
More flexibility, same Security: Our move to Signature-Based SRI
For years, site owners have been using Subresource Integrity (SRI) as a way to ensure that third-party scripts can’t be tampered with. However, keeping your script up to date is one of its challenges.
Safari tracking LCP is finally on the horizon: what’s changing and when
If you’ve been tracking real user performance, you probably already know: Chrome has long supported largest contentful paint (LCP), but Safari until now did not. That’s starting to change, and it’s a big deal if you rely on rumvision for insights.
How to get a lightning fast Magento: an Emico use-case
Magento is a popular e-commerce system worldwide. At RUMvision, we'd like to share how Emico, one of our partners, ensured that their project, Zitmaxx.nl, became one of the fastest e-commerce websites we know of. And yes, this website was built using Magento.
Hyvä Camp Kiel: DevTools + RUM = Great performance
Moin Kiel! I was happy to get everyone up to speed debugging and optimizing Core Web Vitals with RUM + DevTools. Looking for the slides? Here you go!
Slides Mollie Developer Meetup
On July 18th I got to talk about about webperformance, while shipping and sipping at Mollie's biggest developer meetup yet! Here you find the slides.
How to communicate performance to clients as an agency (A practical guide)
Many agencies struggle with performance conversations because they rely on synthetic testing alone. Here's how Real User Monitoring changes the game and what we've learned communicating these insights to clients.
Meet Magento UK 2025 - slides and more info
On June 10th 2025 I gave my talk "Why your pagespeed score is lying to you". In this you'll find the slidedeck, more info on how to improve the webperformance of your Magento shop and even info on a special we're running!
Improving Core Web Vitals for your Hyvä Magento shop: the ultimate SUX guide
"Your site is slow" – four words no Hyvä developer wants to hear, yet only 51% of Hyvä shops achieve good Core Web Vitals scores. After years of optimizing Magento performance, we've identified the common issues preventing stores from reaching their full potential. In this guide, we'll explain not just what to fix, but why things fail in the first place. Your journey to better Core Web Vitals – and happier customers – starts here.
Electricity outage and the impact your revenue
What happens to ecommerce when the lights go out? On April 28, 2025, a massive power outage hit Spain and Portugal just before noon. We combined electricity demand data with our own data, how others experienced it and the impact of an outage on ecommerce and non-ecommerce.
Introducing Baseline: ship modern web features with confidence
You want to ship native lazyloading or popovers to get rid of JavaScript and improve INP. And rather sooner than later. But there's a challenge: how to know if all of your users are ready for that feature?Baseline, a browser-wide initiative tracking 1000+ web features, is changing this. And with RUMvision's Baseline integration, you know exactly when your real visitors are ready for shipping modern features.
Introducing fetchLater API: A new way to collect Core Web Vitals
At RUMvision, we're always looking for smarter ways to optimize web performance data collection. That's why we're excited to announce we've begun rolling out support for a new browser API called fetchLater.
Time to unload your unload events
If you're still depending on unload events in your code, you need to act NOW. Chrome is starting to kill these handlers this month, potentially breaking your website's analytics and data-saving features. These events were never reliable on mobile, Safari already ignores them, and soon desktop Chrome will too. Here's why moving to better alternatives won't just save your code—it'll actually improve your site's performance.
Chrome now ignores Cache-Control: no-store
Chrome is about to supercharge page navigation for millions of websites by ignoring a common performance-killing HTTP header. This under-the-radar change could dramatically improve your Core Web Vitals with zero developer effort by enabling bfcache for pages with Cache-Control: no-store. How do you know if you will benefit? (Spoiler: if you're using Magento, you probably won't.)
Meet bfcache: The 20 percentage performance boost you keep missing
The back/forward cache (bfcache) is the most powerful performance optimization you've never heard of. While teams obsess over milliseconds of server time, they're missing out on entire seconds of improvement that's already built into every major browser.
Modern Image Formats: WebP vs AVIF and its browser support
January 26th, 2024 marks one year since all major browsers fully supported AVIF. For years, developers used `picture` elements to provide WebP or AVIF images while falling back to JPEG for browsers lacking support. Now, with universal AVIF compatibility, these workarounds may no longer be necessary.
Meet Baseline: A standardized browser support status for web features
Keeping up with web technologies can be overwhelming, especially for product owners who aren’t deeply technical or developers who want to avoid the complexity of polyfills. Baseline is an initiative that helps developers and businesses understand which web features are safe to use across all major browsers.