Optimizing LCP (Largest Contentful Paint) is not just reducing the file size of your images, there’s a lot more that goes into optimizing the loading strategy – and you can only grasp where the bottleneck is if you understand the sub-parts that make LCP. LCP is one of the Core Web Vitals metrics that measures […]

How mainframe-era techniques and native browser APIs outperform modern frameworks The Numbers Before the philosophy, the receipts: Frontend (multicardz.com): 32KB JavaScript bundle (15% of minified React) <100KB total payload including HTML, CSS, fonts, everything 0ms Total Blocking Time 0 Cumulative Layout Shift 0.3s First Contentful Paint 100 Lighthouse score Backend: 32ms server processing to select […]

Web performance is a lot like walking on those moving walkways at the airport. When it moves smoothly, you barely notice it. You feel fast. Supported. In control. But when one section stutters, even just a hiccup, your whole body reacts. You lose balance for a moment. You hesitate. Something feels off. Websites behave the […]

performance.now() 2024 was the year we officially launched the W3 RUM Community Group. The idea to form a community group around real user monitoring (RUM) came from the desire to come together as vendors, organizations and even independent consultants to identify opportunities to improve our tooling and push the boundaries of what’s possible. Our goal […]

My website has an animation of clouds moving across the screen. It formerly had an animation of a sun with pulsing waves which is now static. An important performance consideration decided how this came to be in my small website: the almighty compositor. This article is intended to be an approachable story and practical example […]

Loading styles on the web is something that looks trivial at first. You just add a <link rel=stylesheet> to your page (or <style> for inline styles) and you’re done. But if you wanted to load CSS fast, all of the sudden you run into trouble… Assuming you have a traditional web app (or what the […]

Have you heard of React Server Components? Even if you don’t work with React daily, you probably have. It’s been the hottest topic in the last few years in the React Community. And in addition to being the fanciest new toy, Server Components are quite often mentioned in the context of performance. As in, they […]

Remember YSlow? If you do, skip to the next header. YSlow? Back in the olden days circa 2007-ish, there appeared a tool called YSlow. It was a Firefox extension (Chrome wasn’t a thing, not even a sparkle in anyone’s eye) that codified 13 best practices for speeding up web pages based on research by Steve […]

Last year, in the article “5 tips to effectively optimize INP in React,” we focused on what developers often underestimate when optimizing React. React is not automatically fast, and long JavaScript tasks can arise from perfectly common constructs. A larger DOM and more components mean more work during hydration and a slower UI during interaction. […]

Despite its critical importance to online business, web performance is still fighting for attention from key stakeholders. Abstract technical metrics are not enough; people want to see money and the actual influence on revenue. For this, we use data or case studies. But are we really as good at presenting numbers as we think we […]