Large DOM sizes can be a factor in whether interactions are fast or not. Learn more about the relationship between DOM size and INP, and what you can do to reduce DOM size and other ways to limit rendering work when your page has lots of DOM elements.

La webPerf, c’est bien, mais en connaissant toutes les subtilités de la création de notre page c’est mieux \o/. Pendant 45 minutes, nous voyagerons à travers...

Keep your website online, boost performance and improve your digital experience to increase customer conversions.

Waterfaller, this FREE real-time tool leads web professionals through a step-by-step guidebook to boost your website's Core Web Vitals

Driving changes for better loading of third-party resources on the web

Find out what the browser preload scanner is, how it helps performance, and how you can stay out of its way.

In this blog post, we explain the technical details of removing the jQuery library from GOV.UK’s public facing applications and the performance impact it had for our users.

Image CDNs are excellent at optimizing images. Switching to an image CDN can yield a 40–80% savings in image bytes.

Why compressing images for dense screens is different, and how to serve them

How luxury retailer Farfetch's investment in improving Core Web Vitals led to better business outcomes.

Modern CSS rendering performance: The internals of web pages optimization In this talk, we demystify the browser’s rendering pipeline and explore the differe...

Developers started to notice just how big our JavaScript package was and yeah, we knew. We weren’t ignoring the issues; after all, we don’t want the Sentry package to be the cause of a slowdown. But to reduce our JavaScript SDK package size effectively we had to account for shipping new capabilities, like being able to manage the health of a release and performance monitoring, while maintaining a manageable bundle size. After all, new features == bigger package - usually.

This post covers the loading attribute and how it can be used to control the loading of images.

An in-depth course on images for the web.

There has never been a better time to deliver fast, resilient websites, but getting there demands an informed approach. So grab a hot beverage and let this guide illuminate the path forward.

Eagerly loading images within the initial viewport—while liberally lazy loading the rest—can improve Web Vitals while loading fewer bytes.

Too often, any talk of web performance quickly ventures into the land of heavy geekery. Terms like DNS lookups, Gzipping, minifying, far future expires headers, caching, ETags and more are thrown around and consequently lose the attention of most non-techy people. This perpetuates a mentality that p

So often we cram a load of crap onto a single web page and then play silly buggers trying to get them to load efficiently. Instead design for actual performance.

To use web fonts with wide browser support, we need the font files in and format. Who does not care about Internet Explorer, Safari on Mac OS before Sierra...

Formalizing and distributing knowledge about CX is critical. However, there are a few elements of digital government that seem to have been overlooked.

Google Fonts is fast. Now it’s faster. Much faster.

Ever since responsive web design started, we've had a problem with the way images load on the web. Now, Firefox is fixing the problem. Add width & height att...

Grab bag of design tweaks. Like avoiding purple, the slowest color (lie)

In this article, Ken Harker explains what third-party resource requests really are and which common optimization strategies can help reduce the impact on the user experience. By carefully considering how third-party requests will fit into your website during the design stage, you’ll be able to avoid the most significant negative impacts.

Native apps often feature transitions between states that both look great and help communicate the type of navigation to the user. The bad news: creating tra...

An update on the Google Fonts CSS API—how it works, how to use it, and how it can efficiently deliver your web fonts.

I’ve been doing a few audits of late, and one thing that keeps coming up is the use of transition effects on page load (or above the fold content). This post looks at some of the performance pitfalls that can arise from this practice, as well as what you should keep in mind.

This post stems from a conversation I had with a good friend of mine last week. We were talking about how to boost website traffic, and conversions. As I explained to him, and as we'll get to in this post, there's more to the game than just fresh, keyword laden content.

Looking at gaps can help inform performance strategy