Buried at the end of this year’s installment of my semi-annual series on network and device reality is a mystery: multiple, independent data sets from the Web Performance community indicate sites built as Single-Page Applications (“SPAs”) receive, on average, only one (1) “soft navigation” for every “hard” page load. The RUM Archive and Michal Mocny’s […]

Compression Dictionary Transport became an official IETF Proposed Standard this September (congratulations to Yoav Weiss & Pat Meenan 🎉). If you don’t know what they are, I recommend watching Pat’s wonderful performance.now() talk from 2023 – the TL;DR is that you can achieve incredible compression ratios resulting in file sizes a fraction of what we […]

AI is kinda everywhere! Everyone is shipping AI features or Agents, but few of those systems can reason about the complex reality of performance data. This session is a deep dive story into the journey of building a Performance AI assistant and agentic workflows on top of a fork of Chrome DevTools. We’ll explore practical […]

Most developers open Chrome DevTools, check a couple of network requests, maybe refresh the page once or twice — and that’s it. I used to do the same. Over time, DevTools became something else entirely for me. Not just a debugging tool, but a way to understand how the browser actually experiences my code — […]

It’s been a long, busy year but my friend Faisal and I stayed focused on building BasicRUM. After work, we pushed countless commits from a cozy café in Munich. The important news is that we’re wrapping up a few final things, and in Q1 2026 we’ll publicly release the complete BasicRUM source code under a […]

This year, Sergey Chernyshev, Eric Goldstein, and Alex Chernyshev – members of the NY Web Performance meetup – decided to collaborate on the future of the UX Speed Calculator tool Sergey created a few years ago. The initial goal for the tool was to help explain web performance data and how performance impacts business using […]

You’ve heard it many times – third party content can easily cause an otherwise well performing website to become sluggish and slow. And depending on how this content is loaded, it can also introduce single points of failure (SPOFs). When a large cloud provider or content delivery network (CDN) experiences a disruption, their impacts are […]

Introduction The Performance Panel is used for detailed investigations on traces captured during page load or during user interactions. It’s a critical tool for understanding and debugging performance issues, but it can be overwhelming to newcomers. Previously I wrote about the Landing screen released back in Chrome 129 but I didn’t cover recording and analysing […]

This is a step-by-step guide on how I use Chrome DevTools (DevTools from now on) to detect Web Performance issues on a website, as well as validate hypotheses to fix some of the problems found. Disclaimer Before diving in, I want to clarify that: this is not a guide on how DevTools works, it’s a […]

Introduction Modern web performance issues often come from delayed rendering rather than network speed. Client-side hydration and heavy JavaScript pipelines can prevent browsers from showing content as early as they could. Several solutions already exist, like SSR or SSG to mitigate this. They help a lot, but in practice, SSG pages need to be rebuilt […]