What is the mp_ cookie?
The cookie with the mp_ prefix is set by Mixpanel, a product analytics service used by websites and apps to track user interactions (clicks, pages visited, custom events). The full cookie name contains a unique token tied to the site's Mixpanel project, followed by the suffix _mixpanel.
It appears on a site as soon as the Mixpanel JavaScript library (mixpanel.js or an equivalent SDK) is loaded and initialized on the page, typically on the first visit or the first tracked interaction.
What data it stores
The cookie typically stores a unique visitor identifier (distinct ID) and, depending on configuration, session information or user properties set through the SDK. The exact value format can vary by library version and project settings, so it cannot be described precisely here.
The collected data is sent to Mixpanel's servers (global infrastructure, with EU or US hosting options depending on the client's configuration), where it is aggregated for behavior, retention, and conversion funnel reports.
What it is used for
From Mixpanel's perspective, the cookie allows the same visitor to be recognized across multiple sessions and links events to a single profile — essential for retention analysis, funnels, and segmentation.
From the website owner's perspective, this data helps understand how users interact with the product or site: which pages they visit, where they drop off in a flow, and which features are used most — information used for product and marketing decisions, not for Mixpanel serving ads directly.
Does it require consent?
The mp_...mixpanel cookie is classified as a statistics (analytics) cookie. It is not strictly necessary for the website to function, so under the GDPR and the ePrivacy Directive, it requires prior consent from the visitor before being set.
The website operator must disclose this cookie in the cookie policy, correctly categorize it as „statistics” in the consent banner, and ensure the Mixpanel script does not run before the visitor gives consent.
How to block or delete mp_
A visitor can delete or block this cookie from browser settings (Chrome, Firefox, Safari, Edge – cookies and site data section), or use tracker-blocking extensions. Deleting the cookie causes a new identifier to be generated on the next visit.
For website operators, the most effective approach is automatically blocking the Mixpanel script until consent is obtained. A CMP platform such as CookieFix can do this automatically, preventing the Mixpanel script from loading until the visitor accepts the „statistics” category.
Frequently asked questions
It is not dangerous, but it can be considered personal data since it allows a unique visitor to be identified over time, which is why it falls under GDPR.
Mixpanel will generate a new visitor identifier on the next visit, and the prior behavioral history will no longer be automatically linked to the new session.
Yes, as an analytics/statistics cookie, it requires the visitor's prior consent under ePrivacy and GDPR and cannot be set by default.
The typical duration is 1 year from setting or last update, though it can vary depending on the Mixpanel project configuration.