What is the _pk_cvar cookie?
_pk_cvar is a cookie name prefix used by Matomo, the open-source web analytics platform (a Google Analytics alternative) that can run as a hosted cloud service (Matomo Cloud) or be self-hosted on the website owner's own server. The full cookie name includes a numeric site identifier, e.g. _pk_cvar.1.xxxx.
The cookie is created as soon as the Matomo tracking script (typically matomo.js or the legacy piwik.js) runs on the page and logs a visit, whether the site uses Matomo's cloud instance or a self-hosted installation.
What data it stores
The cookie stores so-called visit-scoped "custom variables" – key-value pairs manually configured by the site administrator in the Matomo tracking code, for example user type, page category, or other internally defined segments. The exact content varies completely depending on each site's setup and has no universal fixed format.
Data is sent to whichever Matomo server the site uses (either Matomo's cloud infrastructure or the site owner's own server), not automatically to an external third party, which sets Matomo apart from many other analytics tools.
What it is used for
The cookie's purpose is purely statistical: it lets Matomo segment and analyze traffic data based on the custom variables defined by the site administrator, for instance comparing behavior of logged-in versus anonymous visitors, or visitors in different defined categories.
For the site administrator, this information helps build a more granular understanding of how different audience segments interact with content, without serving targeted advertising purposes.
Does it require consent?
Under CookieFix's classification, _pk_cvar falls into the statistics (analytics) category. Under the ePrivacy Directive (as transposed into Romanian law via Law 506/2004) and GDPR, statistics cookies are not strictly necessary for the site to function, so they generally require the visitor's prior consent before being set, except in rare cases where Matomo is configured in a strictly anonymized mode consistent with guidance from data protection authorities such as ANSPDCP or CNIL.
The site administrator must disclose this cookie in the cookie policy, categorize it correctly in the consent banner, and ensure the Matomo script does not load before consent for the statistics category is obtained.
How to block or delete _pk_cvar
A visitor can delete or block _pk_cvar via browser settings (Chrome, Firefox, Edge, Safari – per-site cookie management) or by declining the "statistics" category in a compliant consent banner.
- Manually deleting cookies for the domain
- Using the browser's private/incognito mode
- Tracker-blocking browser extensions
- Using an opt-out option if offered by a given Matomo installation
For site administrators, a CMP such as CookieFix can automatically block the Matomo script from loading until the visitor gives consent for the statistics category, helping ensure technical compliance.
Frequently asked questions
No, it's an analytics cookie used for traffic statistics, not for ad tracking or collecting sensitive personal data.
Because it's a session cookie used to define visit-scoped variables; the short duration reflects Matomo's standard session timeout.
Generally yes, since it's classified as a statistics cookie; an exception applies to strictly anonymized Matomo configurations that follow data protection authority guidance.
Yes, the data goes to the site's own Matomo server (cloud or self-hosted) rather than to a global third party like Google, giving the site administrator more control.