The Site Kit plugin acts as a “facilitator” between WordPress sites and the Google services that you choose to connect with your site. The only code that the Site Kit plugin itself adds to the front-end of your site is a meta tag, which you’ll notice below when checking your site’s source code:

<meta name="generator" content="Site Kit by Google [plugin version]" />

For each connected Google service, Site Kit will also add the appropriate code snippets on the front-end to allow for requests between the service and your WordPress site. If you choose to connect to AdSense, Site Kit will place the code snippet to display ads, as well.

Site Kit adds these snippets as per each service’s recommended placement. Site Kit makes the same http requests that are made when such Google services are connected manually. Integrating Analytics, for example, will result in an http request to Google Analytics, whether you implement Google Analytics manually or via Site Kit. 

In the back-end of your site, Site Kit adds code to enable its own functionality, including managing connections to Google services, providing the Site Kit dashboard, and more. This does not impact your site’s front-end performance, as these operations only occur in the WordPress administrator panel.

We take reports of issues with site performance very seriously. If your site is experiencing slowness or other performance issues with Site Kit installed, please create a new topic on our support forum so that we can take a look.

Frequently asked questions

Why did my performance score go down when using Site Kit?

If you’ve set up Site Kit and connected services such as Google Analytics, Tag Manager, or AdSense within the plugin, `http` network requests will be made to these services as needed on the front-end of your site. These requests are necessary in order to provide communication between your site and these services. Network requests can have a slight impact on performance dependent on many factors, including client or server conditions, network latency, and network congestion. 

These network requests are not Site Kit-specific requests. The same network requests would be made if you uninstalled Site Kit and instead connected these services manually. 

What code does Site Kit add to my site?

Upon installing and setting up Site Kit, the plugin will only insert a meta tag on the front-end of your site. If you choose to connect additional modules, such as Google Analytics or AdSense, Site Kit adds the code snippet as recommended by these Google services. For example, if you choose to connect the Analytics module within Site Kit, the plugin will insert the Google Analytics code snippet as suggested by the Google Analytics service

Examples of all possible code snippets that Site Kit can add to a site are available here.

When a user is logged in as an administrator, additional code is added in relation to the Site Kit admin toolbar. This code is not added for non-administrator users or visitors to your site. It is also not visible if you’ve disabled the Site Kit plugin’s admin toolbar feature. This code does not impact your website’s performance score on PageSpeed Insights.

How do I compare performance with and without Site Kit?

If you’re planning on connecting Site Kit and connecting various Google services, consider that each service you connect will result in your site communicating with these services. This can have a slight performance impact.

If you wish to compare performance with Site Kit active and without, a more realistic comparison is to compare performance with the same services added manually, and not using Site Kit (ie. Google Analytics, AdSense & Tag Manager).