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Jetpack Boost

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

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

If you want to know more about the Automated Critical CSS feature for paid subscriptions, click here.

Getting Started

What do I need in order to run Jetpack Boost on my site?

  • The latest version of WordPress. If your version of WordPress is out of date, you’ll see a prompt to automatically upgrade with a single click, or you can upgrade manually.
  • A account. Don’t have one yet? Sign up for one here, or create one during the Jetpack Boost connection flow. You only need one account to access all of our services (including Akismet, Crowdsignal, Gravatar, and itself) so if you use any of these services you already have a account you can connect to Jetpack Boost.
  • A publicly accessible WordPress site: no password protection or Coming Soon / Maintenance Mode plugin in use.
  • A publicly accessible XML-RPC file.

How to Install Jetpack Boost

Installing Jetpack Boost from WP Admin

The first option is to install Jetpack Boost from within your WP Admin.

To begin, click on the Plugins link, then click Add New.

Search for Jetpack Boost. The latest version will be in the search results. Click the Install Now button:

Jetpack Boost Plugin

Next, click the Activate button. 

After activating, go to the Jetpack Boost menu item:

Jetpack Boost Menu

and click on the Get Started button:

Get Started in Jetpack Boost

The scores will then be calculated for both Mobile and Desktop as shown below:

Command Line Interface Installation

If you have installed WP-CLI, you can install Jetpack Boost by running this command:

wp plugin install jetpack-boost

Configuring Jetpack Boost

Currently, the plugin has 3 performance features, which can be enabled or disabled via the Jetpack Boost menu in WP-admin:

  • 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. A link to a new Advanced Critical CSS recommendations page displays after you’ve turned on this feature and the optimization has run, which gives customized suggestions. Read more about critical CSS generation at
  • 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
  • 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. Note: If you use Jetpack Boost with the Jetpack plugin, turning Lazy Image Loading on and off will turn the Lazy Images feature in the Jetpack plugin on and off as well. Read more about lazy image loading at

When you first visit the Jetpack Boost dashboard, your current score for Mobile and Desktop will be calculated. (This may take a few minutes).

When you enable or disable any of the Boost options, you can click the ‘Refresh’ link to calculate your new scores.

Enabling the JavaScript and Lazy Image options is instantaneous, but when you enable Critical CSS, your Critical CSS will be generated. This can take some time, depending on the size of your site.

Frequently Asked Questions

Do I need Jetpack for Jetpack Boost plugin to work?

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

Does it work on a multisite installation?

Yes. If you are using WordPress Multisite, Jetpack Boost must be installed and activated separately on each site in the network (on sites where Jetpack Boost connections are desired).

Any Administrator for that site can create the Jetpack Boost connection. It does not have to be a different Administrator user or a different user for each site.

I have a local WordPress install or a private site. Can I use Jetpack Boost?

Yes, “Offline Mode” now allows testing of Jetpack Boost on local environments easily.

Can I use Jetpack Boost in combination with other performance plugins?

Jetpack Boost and other optimization plugins may have similar optimization options available. Jetpack Boost options can be easily turned on and off, and other plugins usually will offer the same facility too.

We don’t recommend having the same optimization enabled in Jetpack Boost and other optimization plugins, as it is unlikely to benefit your site and may cause unexpected issues.

How do I install Jetpack Boost in my language?

Once you have installed WordPress in your own language, Jetpack Boost will automatically switch to your language, as long as a translation file is available. You can check for existing translations or help translate the plugin here.

How is Critical CSS generated?

This link explains a bit more about critical CSS generation. To add to that, hard-coded/inline CSS is not included in Critical CSS, because it is already inline on the page.

Where is the Critical CSS stored?

The Critical CSS is stored in the database posts_table as a custom post type.

Is Critical CSS generated for mobile versions of my site?

We don’t generate specific CSS only for mobile, but we do take samples of the site with both wide and narrow screen sizes and then combine them so that the Critical CSS produced is valid for both mobile and desktop devices.

How do I exclude some JavaScript files from being deferred?

If you experience unwanted behavior when you defer JS with Boost, it could be that the affected functionality relies on the JavaScript files being in a certain order or being made available to the page as soon as possible.

In such cases, you can tell Jetpack Boost not to defer those specific files by adding the attribute data-jetpack-boost="ignore" to the script tag.

E.g. <script data-jetpack-boost="ignore">.


I’m having trouble getting Jetpack Boost connected to How can I troubleshoot?

Please see the documentation on Jetpack connection issues as the connection flow between Jetpack and Jetpack Boost is similar.

Get help

You can post a support request on the Jetpack Boost Plugin Support page.

Privacy Information

We are fully committed to the privacy and security of our customers and their personal data. For a better understanding of how Jetpack Boost uses your data, please refer to the  Privacy Notice (Automattic owns and operates the Jetpack Boost plugin), the Automattic Privacy Policy, and the following section.

More information about the data usage on your site

Jetpack Boost uses Jetpack libraries to connect to and calculate the page speed score (making use of the tk_ai cookie). There is more information about cookies within Jetpack here.

Data Used
Site Owners / Users

In order to calculate Page speed scores, generate Critical CSS blocks, etc, the following information is used: site ID, local site ID, and site URL. Additionally, for activity tracking (detailed below): IP address, user ID, username, site ID and URL, Jetpack version, user agent, visiting URL, referring URL, timestamp of event, browser language, country code, Critical CSS generation URL, block counts, block sizes, error details, generation time, provider keys, Boost version, and active Boost features.

Site Visitors


Activity Tracked
Site Owners / Users

We track when, by which user, and which website is connected to and when the plugin is deactivated. We also track activities such as the Critical CSS generation process, when, and which, configuration settings are modified.

Site Visitors


Data Synced (Read More)
Site Owners / Users


Site Visitors


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