What is the _clck cookie?
Stores a unique, pseudonymous user ID to ensure subsequent visits to the same website are attributed to the same user profile for Microsoft Clarity analytics.
Table of Contents
About the _clck cookie
| Vendor | Microsoft |
|---|---|
| Category Category The functional category of the technology, such as Web Analytics or Social Media. Learn more | Heatmap & Recording |
| Consent Category Consent Category The consent category this cookie most commonly falls under across sites we scan, normalized into four standard categories. Learn more | Performance & Analytics |
| Prevalence | Very Common |
| Popularity Popularity Popularity is calculated from our dataset of 4.5B+ cookies analyzed across hundreds of millions of web pages. Learn more | Found on 11.4% of scanned pages |
| Expiration Type | Timestamp |
| Expiration Duration | 30 days |
| Party Type Party Type Whether the cookie is first-party or third-party. Learn more | 1st-Party |
| Risk Level Risk Level Rates how sensitive the data stored by this cookie is (High, Medium, or Low) based on data classification and distribution. Learn more | Medium |
| Vendor Privacy Policy | https://privacy.microsoft.com/en-us/privacystatement |
| Vendor Website | https://www.microsoft.com |
What is the purpose of the _clck cookie?
The _clck cookie is a first-party cookie set by Microsoft Clarity, a behavioral analytics tool that offers heatmaps and session recordings. This cookie is used to store and persist a unique, pseudonymous Clarity User ID and user preferences specific to that site. By retaining this ID on the user's browser, Clarity ensures that a user's behavior across multiple subsequent visits to the same website is accurately attributed to the same user profile. This enables aggregate behavioral analytics and comprehensive session stitching.
What are the Privacy Risks of the _clck cookie?
Risk Level: Medium
The _clck cookie captures pseudonymous behavioral data, such as mouse movements, clicks, and page interactions, utilizing a persistent unique user ID to track a visitor across multiple sessions on a website. Although Clarity is designed to mask sensitive data by default, the behavioral tracking nature and the persistence of the identifier across a typical one-year lifespan present a medium privacy risk, as it profiles user interactions across the site over time.
How to Remove the _clck cookie from a Website
Website administrators can remove the _clck cookie by removing the Microsoft Clarity tracking script (clarity.js) from the website's source code or tag manager. Alternatively, administrators can disable cookies within the Clarity platform by navigating to Settings > Setup, and under Advanced settings, toggling off the 'Cookies' option. When this setting is turned off, Clarity will continue to track user sessions but will not set cookies, treating each page navigation as a new user session.
This definition was last reviewed on August 19, 2026. ObservePoint regularly reviews these definitions to ensure our customers have the most up to date information about the cookies on their websites.