Everything, On the Main Thread, All at Once Arrays are in every web developer’s toolbox, and there are a dozen ways to iterate over them. Choose wrong, though, and all of that processing time will happen synchronously in one long, blocking task. The thing is, the most natural ways are the wrong ways. A simple […]

Let’s talk about font fallbacks and how we can craft these to to perfection in order to reduce layout shifts and our users’ headaches. Who among us has not experienced the horrors of clicking the wrong thing because stuff moves? Arghhhh! I’ll start with a brief intro and then focus on lessons learned (the hard […]

There was once a farmer who wanted his chickens to lay more eggs. His friend, a physicist, said – “I can give you a solution for your problem if you have a spherical chicken kept in vacuum” Looking at performance problems in the real world often reminds me of this scenario. Here’s a map from […]

I’m passionate about Web Performance—from identifying performance issues, monitoring (synthetic and RUM), metrics, implementing product culture, training development teams and other stakeholders, speaking at meetups and conferences, tools, and snippets. When it comes to tools, my favorite is Chrome DevTools. They are integrated into the browser (desktop, that is), making it quick and easy to […]

Compression dictionary transport is a relatively new feature in HTTP that allows for using custom compression dictionaries to improve the compression of HTTP responses. The results can be pretty dramatic, with responses anywhere from 60-90+% smaller than using the best non-dictionary compression currently available. The feature has been under experimentation in Chrome over the last […]

TL;DR: In this article I am sharing the good news that Web Performance Optimization is being studied in universities and I am laying out the plan of teaching Real User Monitoring which I will do for the first time in front of students. My hope is to share ideas in case other fellows would be […]

As a web performance consultant, I frequently rely on visual data to prioritize optimizations and troubleshoot regressions. Over the past year, two types of graphs have stood out for their effectiveness in simplifying complex data and speeding up decision-making. The Prioritization Graph: Where to Start? When optimizing web performance, the first step is identifying the […]

It’s a shame that so many redesigns end up slowing down the site or dropping conversions. How to prevent this? In this text, based on one of our successful projects, you will get a framework for web redesign management. We are a small team of web performance consultants with years of experience and a good […]

As web performance experts, we’re all familiar with the oft-cited examples: Amazon, Walmart, and their gains or losses directly tied to page loading speeds. But while these examples are inspiring, they prompt an essential question: what about your company? Your users, buying cycles, and challenges are unique. The real question is not whether web performance […]

Nearly one in five websites is secretly sabotaging its own performance through a single CSS feature that’s been known to be problematic for over a decade. Based on our analysis of over 16 million mobile websites, there’s a good chance you might recognize this in your own codebase 😉 The culprit? CSS @import. While its […]