Jetpack Boost


Jetpack Boost provides one-click optimizations that supercharge your WordPress site’s performance and improve web vitals
scores for better SEO.

Performance Modules

Optimize your site with the same techniques used on the world’s most successful websites. Each technique is packaged up as a module that you can activate and try out.

Currently the plugin has 3 performance modules available:

  1. Optimize CSS Loading generates Critical CSS for your homepage, posts and pages. This can allow your content to show up on the screen much faster, particularly for viewers using mobile devices.

    Read more about critical CSS generation at

  2. Defer Non-Essential Javascript moves some tasks to after the page loads, so that important visual information can be seen sooner.

    Read more about deferring javascript at

  3. Lazy Image Loading only loads the images the user can see. As the user scrolls, images are loaded just before they show up on the page. This simple optimization makes sites faster and saves bandwidth for your host and your customers.

    Read more about lazy image loading at

Easy Setup

There’s nothing to configure – the setup process is as easy as:

  1. Install the plugin
  2. Activate Jetpack Connection
  3. Turn on performance modules one by one and observe how the performance score changes

    Google PageSpeed API is used to measure the performance score of a site. It’s important to look at the PageSpeed score because Core Web Vitals are going to be used as a ranking factor in search engines.

With 💚 by Jetpack

This is just the start!

We are working hard to bring more features and improvements to Jetpack Boost. Let us know your thoughts and ideas!

We’d also like to give a special THANK YOU to the XWP team who provided help with initial research and scoping of the plugin and were engaged with our team throughout the project.


  • Manage your Jetpack Boost settings


  1. Install Jetpack Boost via the plugin directory, and activate it.
  2. Visit the „Jetpack Boost“ section of your site’s WP Admin.
  3. Turn on the performance features you would like to try out on your site.


What are Web Vitals?

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

How do I know if it’s working?

Every site is different and so performance benefits for each module may vary from site to site. That’s why we recommend that you measure the performance improvements on your site by enabling the performance modules one by one. There are many tools out there that you can use for free to measure performance improvements:

Google PageSpeed measurements are built-in the Jetpack Boost dashboard.

Does it work with static page cache?

Absolutely! If you have plugins like WP Super Cache or W3 Total Cache installed – Jetpack Boost is only going to help increase the performance benefits! Keep in mind that you need to wait for the cache to clear for Jetpack Boost improvements to show up.

Does this plugin require Jetpack?

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.


1. Juli 2021
I already apply a high level of optimisations to my websites. But I observed the following on a difficult site. Critical CSS generator actually works BUT.... What this did was remove the renderblocking warning in Lighthouse. It actually increased the LCP score - This is because the item that was the LCP element was no longer the LCP element - Changing the score negatively. Further playing around with settings is required. Defer JS Other scripts already deferred by standard setup What this did was move my inline cookie plugin to the footer - Really having little impact on site load times but possibly breaking the cookie control for the site. Lazy Load Having had issues with lazy load modules before (jetpack standard lazy load has no real control and lazy loads everything even above the fold...) - I normally opt to just use the loading='lazy' settings that come with the theme I use. This is accepted as a pass in web vitals and gives more control on which images are lazy loaded. This lazy load module seems much better than the one included in standard jetpack and has not added another render blocking script.
9. Juni 2021
After activating Jetpack Boost, I got the following errors. [Whoops, something went wrong Couldn't get the site score Retry Timed out while waiting for metrics] Help me.
7. Mai 2021
While I could enable Defer Non essential Javascript and lazyload options to boost my site, Got the following errors again and again. 1) The calculating score tabs, for desktop & Mobile, are not working. They keep rolling for several minutes and in the end got this: "Whoops, something went wrong Couldn't get the site score Retry Timed out while waiting for metrics" 2) "An error occurred while sending Critical CSS generation results to the server: Failed to fetch"
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  • Update: User connection is no longer required for Speed Scores.
  • Update: Completely revamped how site speed scores are retreived.
  • Update: Reduced backend dashboard JavaScript bundle size.
  • Update: Added a message to explain how site score is calculated.
  • Update: Added „Offline Mode“ to allow testing Jetpack Boost on local environments easily.
  • Update: Improved error handling and the error messages provided.
  • Update: Improved Critical CSS Generation stability.
  • Update: Remove animations from Critical CSS.
  • Fix: Incompatibility with UsersWP and similar plugins that might introduce redirects during Critical CSS Generation.


  • Fix: Failed to execute ‚json‘ errors
  • Fix: Connection UI Border issues
  • Update: Improve Jetpack compatibility
  • Update: Improve Critical CSS Compatibility with caching and minification plugins
  • Update: Clean up JavaScript dependencies


  • Fixed: Defer JavaScript compatibility with XML Requests


  • Fixed: Web Stories compatibility
  • Improved: „Defer Non-Essential Javascript“ module compatibility with other plugins


  • Updated: Support for AMP Plugin 2.0+
  • Updated: No longer defer JavaScript on POST, AJAX, Cron requests and sitemaps.


  • Improved: HTML Media tag handling
  • Fixed: Metrics timeout caused by caching in the REST API


  • Fixed: An issue where the connection iframe would sometimes break
  • Updated: On connection: showing an XML RPC Error instead of HTTP 500 when XML-RPC is disabled


  • This update brings a lot of stability improvements.
  • We’ve been hard at work to get here and Jetpack Boost v1.0.0 is finally here! 🎉


  • We’ve refactored the plugin quite a bit, starting from the UI to stability fixes.


  • First public alpha release