What is the personalization_id cookie?
personalization_id is an HTTP cookie set by X (formerly Twitter) when a visitor interacts with X content embedded on a website — for example an embedded tweet, an X share button, or a tracking widget used by advertisers.
The cookie is typically dropped as soon as a script from platform.twitter.com or a similar widget loads on the page, whether or not the visitor has an X account.
What data it stores
The cookie holds a randomly generated unique identifier tied to the visitor's browser. The value itself does not directly contain a name or contact details, but it allows the same device to be recognized across visits to different sites that embed X content.
Data collected through this identifier is sent to X's servers (X Corp., based in the US) and may be combined with other browsing activity to build an interest profile.
What it is used for
For X, personalization_id helps measure engagement with X widgets on third-party sites, personalize ads shown within the X platform, and analyze advertising campaign performance.
For the website owner embedding X content (tweets, share buttons), this cookie provides no direct benefit — it is part of X's own advertising and tracking infrastructure, activated automatically once the widget loads.
Does it require consent?
It is classified as a marketing cookie (advertising/tracking), since it involves tracking visitor behavior across multiple sites. Under the ePrivacy Directive (as transposed nationally) and GDPR, placing it requires the visitor's prior consent.
- Site owners must list this cookie in their cookie policy, naming X as the provider and its actual duration.
- X widgets (embeds, buttons) should not load before consent for the marketing category is obtained.
- Declining consent must not block access to the rest of the site's content.
How to block or delete personalization_id
A visitor can delete this cookie from their browser's settings (Chrome, Firefox, Edge, Safari) under cookie management for twitter.com/x.com, or use private browsing mode. Tracker-blocking extensions can also prevent it from being set.
For site owners, the script loading X widgets should be blocked until consent is given. A consent management platform such as CookieFix can automatically stop these embeds from loading and enable them only after the visitor accepts the marketing category.
Frequently asked questions
It's a marketing cookie set by X (formerly Twitter) to recognize a visitor's browser and personalize content and ads related to the X platform.
Typically around 2 years, though the exact duration can vary as X updates its policies.
Yes, as a marketing/tracking cookie it requires the visitor's prior consent under GDPR and the ePrivacy Directive.
You can delete it from your browser settings or use tracker-blocking extensions; compliant sites should only load it after consent is given.