In March 2021, the developers of the Jetpack plugin had introduced the Jetpack Boost plugin that has been built for users who are unhappy with their WP site’s LCP, CLS, and FCP scores. You can download the Jetpack Boost plugin from the WordPress repository. This plugin is free and open-source. Is the plugin able to improve the site’s CWV/Core Web Vitals score? It is easy to set up. Here’s my honest review of the Boost plugin:

Review of the Jetpack Boost plugin

jetpack boost plugin

When you install and activate the Jetpack Boost plugin, you will see a notice box with the button “get started” click the button. Click this button. You’ll now see a page that introduces the plugin. Click this button to activate the green button labeled “Get Started”. Now you’ll be asked to log into your Jetpack account via WordPress or Google. Jetpack Boost will now run the page speed testing and display the page’s score on desktops and mobile devices. JB will display the three toggle options below the scores: Optimize CSS structure; Defer Non-Essential JavaScript; Lazy Image Loading. You must activate the options you choose. Here are the toggle options you’ll find below the page speed scores:

Lazy Loading: Lazy loading is enabled by default in the latest WordPress release. This feature is only available to users of WordPress 5.5 or older. What is lazy loading? Lazy loading ensures that the only images in front of the user are loaded.

Defer nonessential scripts: This option of the Jetpack Boost plugin will execute nonessential JS scripts after the page loads. This will speed up the page’s loading time.

Optimize CSS structure: Out of the 3 features, the Jetpack Boost plugin’s critical CSS option i.e. Optimize CSS structure is the most powerful and interesting feature. Critical CSS will increase the CWV’s LCP/FCP scores. This plugin will automatically generate critical CSS for your website when you activate it. After the CSS has been generated, the plugin will insert the critical CSS code into the HTML title tag.

*How important is critical CSS? You will see a significant improvement in your LCP/FCP scores if you include critical CSS to the website. I tried to manually generate critical CSS on my VPS using an npm module. It was then included in the heading section of the WP site. While I was able generate critical CSS, it was not easy. I had to do this each time a theme or plugin was changed. Until now, you had to rely on external tools and paid plugins such as wp rocket to use the critical CSS feature. WP Rocket’s single site license starts at $49/year. Jetpack Boost automatically inserts the necessary CSS into your WP site pages and generates it for you.

Clear cache: If you update the theme or plugin, you can regenerate the critical CSS and clear the cache.

Is the plugin effective?

My SaaS’s blog page had a page speed score of 92 before installing and configuring the plugin. After setting up the plugin, the score was 100%. See the below screenshot:

100 pagespeed score

Closing words

Although you will find several caching plugins, none of the plugins offer a free critical CSS generator function like Jetpack Boost. The plugin can significantly improve your website’s page speed score in a matter of seconds. WordPress made it easier for users by introducing Jetpack Boost, a plugin that optimizes your website’s Core Web Vitals Score in just a few clicks.