Jetpack Boost – Website Speed, Performance and Critical CSS

Jetpack Boost makes small changes to the way that data is sent from your WordPress site to your users’ browser, to enable the browser to display your site faster.

Jetpack Boost includes a growing number of separate features which can be turned on individually to improve your site’s performance. These include:

Website Performance is complicated and can be affected by a number of factors. As a result, it is difficult to accurately predict how much impact it will have on each site.

Generally, the lower your speed score is to begin with, the more Jetpack Boost may impact your performance. We have seen user reports of up to 25 Speed Score points improvement simply by installing and using Jetpack Boost.

Jetpack Boost automatically defers non-essential CSS when its “Optimize CSS Loading” feature is enabled and Critical CSS has been generated.

The “Optimize CSS Loading” feature identifies the most important CSS rules your site needs to display your pages as quickly as possible (commonly called “Critical CSS”), and defers all other CSS rules from loading until your main content has loaded.

Web Vitals are the measurements that Google uses to better understand the user experience on a website. By improving Web Vitals scores you’re also improving the user experience on your site.

You can read more about Web Vitals on web.dev

Each Core Web Vital relates to an aspect of how quickly your site can load and appear on new visitors’ screens.

Jetpack Boost makes small changes to the way that data is sent from your WordPress site to your users’ browsers, to enable your content to load faster. As a result, it can improve your Core Web Vitals scores.

Jetpack Boost is a part of the Jetpack brand, but it doesn’t require Jetpack plugin to run. This is a separate plugin from Jetpack and it will always remain that way.