fontaine VS web-vitals

An alternative to Capsize for reducing font swap layout shift is Fontaine. It has a Vite plugin, and is able automatically to update font face CSS (like we will do, using Capsize metrics). We do something a little more manual here with Capsize, just to help get a grounding in the issue and solution approach.

Fonts are one of the biggest pain points in the context of performance optimization. I have decided to not use any CDN like Google Fonts but instead, I'm serving them myself. Also, I have used a cool package called Fontaine which reduces CLS by using local font fallbacks with crafted font metrics.

I started using fontaine on my blog. If you haven't tried it out, you can find it here. It helps reduce Cumulative Layout Shift. The flash of unstyled content jank that you can see when you first land on a site, before fonts have loaded. I can't see why that would be an issue. It should improve my blogs Core Web Vitals and help stuff rank better, not worse. I think this is a red herring.

Custom font usage can introduce cumulative layout shift (or "jank") to your website. This post shows how to use fontaine to reduce this with Docusaurus sites.

Google Core Vitals now represent the most important metrics to focus on when it comes to technical SEO. Google Core Vitals are a set of standardized metrics that Google uses to evaluate the user experience offered by a web page and assign it a technical SEO grade. Several tools exist to measure and report technical SEO performance, but the most reliable is Google Lighthouse.

-https://www.patterns.dev/ -https://github.com/reactjs/rfcs/blob/main/text/0188-server-components.md -https://dev.to/this-is-learning/qwik-the-post-modern-framework-3c5o -https://dev.to/this-is-learning/astro-framework-169m -https://developers.google.com/web/updates/2019/02/rendering-on-the-web -https://web.dev/vitals/

Image source: https://web.dev/vitals/

You will be pleased to know that isn’t actually the case and it’s a suite of metrics instead known collectively as core web vitals https://web.dev/vitals/

Let's go back to 2020, this was when Google made a big change regarding their performance rating -- they introduced the Core Web Vitals. I want to discuss this timeframe because it was the last point where there is clear comparable data between the performance metric set (5 metrics) and the Core Web Vitals (3 metrics). The Core Web Vitals is a subset of the performance metric set.

Beyond elevating the user experience, another clear benefit of speeding up the rendering of a website is search engine optimization (SEO). Speed is so important to ranking well on search engines that it’s included in Google’s published description of what their indexers use to rank websites for performance, called Core Web Vitals.

This is something we won't ever be able to measure, as it depends on how people perceive the overall experience on their device, but it boils down to perceived performance. So by all means, optimize your mobile apps and web frontends, test on old devices and slow networks (even if only emulated), and monitor their real-user performance (e.g. through Web Vitals). As part of performance testing, have a look on electricity use, as it will both be directly associated with emissions to produce that electricity, and be perceptible by the user (battery drain). And don't forget to account for the app downloads as part of the overall perceived performance: light mobile apps that don't need to be updated every other day, frontend JS and CSS that can be cached and won't update several times a day either (defeating the cache).