About Cookies in Klaviyo

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Klaviyo uses cookies as a part of our web tracking model to gather information to improve conversion rates and email performance. This article explains the specific cookies we use and their purposes so that you remain informed on how customers are tracked. This likewise enables you to remain compliant with national and international regulations, and gain awareness around how Klaviyo gathers data.

In order to maintain GDPR compliance, you will want to display links to your Privacy Policy, Terms of Service, and cookie policy in all of your emails.

Klaviyo Tracking Cookies

There are two main cookies that Klaviyo uses by default when Klaviyo JavaScript is turned on: 

Cookie Purpose
__kla_id Tracks when someone clicks through a Klaviyo email to your website
KL_FORMS_MODAL Tracks when someone subscribes (opts in) to a form

Once a user is identified, the web cookie will last for two years. If JavaScript options are off, customers will not be cookied; however, you will not have access to web tracking and signup forms.

Due to a Safari update entitled ITP 2.1, cookies gathered while using the Safari web browser expire after seven days rather than lasting the full two years.

If you want to maintain Klaviyo JavaScript but remove a cookie, there is one workaround. Toggle the Klaviyo tracking on and off by creating a new cookie, __kla_off, and running document.cookie = "__kla_off=true".

Using API to Access Cookies

Using API to access cookies is useful to check whether or not Klaviyo can identify a customer. You can do this by running JavaScript and typing in _learnq.isIdentified(). The response will then either be true or false.

Email to Website Tracking

When email to website tracking is enabled, Klaviyo identifies individuals that click through a Klaviyo email and browse your website. You can toggle on and off Klaviyo's ability to track email to website activity in your account's email settings.

9/20/21 Update: with the release of iOS 15, macOS Monterey, iPadOS 15, and WatchOS 8, Apple will change the way that we receive open rate data on your emails by prefetching our tracking pixel. With this change, it’s important to understand that open rates will be inflated.

If you have over 1,000 opens, we suggest moving to utilize click rate data as your engagement driver. It may also be useful to look at the number of iOS-specific users within your data to understand how your open rates will change.

For complete information on ways to potentially mitigate these Apple open changes, visit our iOS 15: How to Prepare for Apple’s Changes guide.

To navigate to your email settings page click Account > Settings > Email


When this is on, we add an additional parameter to all URLs in your emails to track activity. This is called the _kx parameter, and _kx will appear directly in the URL. The unique encrypted value is then decrypted by our web tracking and allows us to identify the user that clicked through the URL. 

To learn more, check out our article on Klaviyo web tracking.

Additional Resources

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