personalization_id Cookie: What It Is, Who Sets It, and Consent Rules

What the personalization_id Cookie Does on Your Site

The personalization_id cookie is a third-party advertising cookie that X sets on .twitter.com to track the activity of a browser on and off X. The personalization_id cookie "tracks activities on and off Twitter for a personalized experience", according to the X help page on cookies. The X Pixel on your page sends each visit to analytics.twitter.com, and the response of X sets the personalization_id cookie on .twitter.com. X links the visit to the same browser on X and uses the link for ad measurement and audiences.

The personalization_id cookie never sits on your own domain. The X Pixel writes its own first-party cookies on your domain, such as the _twclid cookie for the click ID of an X ad.

Who Sets the personalization_id Cookie

The X Pixel loads uwt.js from static.ads-twitter.com and reports each visit to the endpoint analytics.twitter.com/1/i/adsct. The response of that endpoint set the personalization_id cookie on .twitter.com, together with the guest_id, guest_id_ads, and guest_id_marketing cookies, in a TermsFeed check on 17 October 2026. A second request to t.co/1/i/adsct set the muc_ads cookie on t.co.

The X Pixel wrote 3 first-party cookies on the test site at the same time, _twpid, _twclid, and _twsid. The _twclid cookie held the twclid click ID from the landing page URL, which X adds to the links of X ads.

Read how X Corp. handles the data in the X Pixel privacy policy, and sign the X Controller-to-Controller Data Protection Addendum before you collect data from visitors in the EU or the UK. Both documents appear in the sources at the end of this page.

Does the personalization_id Cookie Need Consent?

Yes, the personalization_id cookie needs consent in the EU and the UK, and needs no prior opt-in in California. The table gives the rule for each law.

The consent table describes what each law requires and is not legal advice. Whether a law applies to your site depends on where your visitors are, where your business is based, and how you set up the X Pixel, such as the first-party cookie setting of the X Pixel.

The ePrivacy Directive requires consent before a site sets the personalization_id cookie. The General Data Protection Regulation (GDPR) sets the standard for that consent: freely given, specific, informed, and unambiguous.

The UK Privacy and Electronic Communications Regulations (PECR) require consent before a site sets the personalization_id cookie.

The California Consumer Privacy Act (CCPA) sets no general opt-in requirement before a site sets the personalization_id cookie. The CCPA treats the data the personalization_id cookie collects for cross-context behavioral advertising as sharing. Offer visitors a way to opt out of sale and sharing, such as a "Do Not Sell or Share My Personal Information" link or the alternative opt-out link the CCPA regulations allow. Honor Global Privacy Control (GPC) signals as opt-out requests. Sharing the data of a consumer under 16 needs opt-in consent instead: from the consumer from 13 to 15 years, and from a parent under 13.

Read how each law decides which cookies need consent in the EU ePrivacy Directive + GDPR guide, the UK PECR guide, and the California CCPA guide.

How to Block the personalization_id Cookie Until Visitors Accept

Block the personalization_id cookie by holding back the X Pixel base code until the visitor accepts advertising cookies. TermsFeed Free Cookie Consent and TermsFeed Privacy Consent place the X Pixel in the advertising category. Check whether an exemption applies to your own use of the X Pixel in the consent rules for the personalization_id cookie.

The X Pixel triggers no personalization_id cookie while the base code waits as a tagged script, because the browser sends no request to analytics.twitter.com for a visitor who declines.

<script type="text/plain" data-cookie-consent="targeting">
!function(e,t,n,s,u,a){e.twq||(s=e.twq=function(){s.exe?s.exe.apply(s,arguments):s.queue.push(arguments);
},s.version='1.1',s.queue=[],u=t.createElement(n),u.async=!0,u.src='https://static.ads-twitter.com/uwt.js',
a=t.getElementsByTagName(n)[0],a.parentNode.insertBefore(u,a))}(window,document,'script');
twq('config','YOUR_PIXEL_ID');
</script>

How to Verify That the personalization_id Cookie Waits for Consent

Verify the setup in a private window. Open Chrome DevTools, select the Application tab, and open Cookies. Click "I decline" on the consent banner and reload the page. The personalization_id cookie must not appear in the list until you accept advertising cookies.

How Long the personalization_id Cookie Lasts

The personalization_id cookie lasts 2 years (730 days). Chrome keeps the cookie for 400 days (about 13 months) at most, according to the Chrome team.

The response of X set the personalization_id cookie with a Max-Age of 2 years (730 days) in a TermsFeed check on 17 October 2026. Chrome keeps the cookie for 400 days at most. The X help page on cookies gives no lifetime for the personalization_id cookie and states that X caps cookie lifespans at 13 months "in certain areas". The TermsFeed Privacy Consent template listed 13 months.

Cookies That Work Together With personalization_id

The X Pixel sets 7 other cookies next to the personalization_id cookie in its current setup.

Scripts and Requests of the X Pixel That Come With the personalization_id Cookie

The catalog lists 2 scripts, pixels, and data endpoints of the X Pixel, which a cookie scanner or the Network tab of Chrome DevTools shows next to the personalization_id cookie. Block the main script, and the requests in the table stop with the main script.

personalization_id Cookie FAQs

Is personalization_id a necessary cookie?

No, the personalization_id cookie is not a strictly necessary cookie. Firstly, your site works the same for a visitor who refuses the X Pixel. Secondly, X uses the personalization_id cookie to track activity "on and off Twitter", a purpose the ePrivacy Directive exemption does not cover. Thirdly, the X help on conversion tracking asks advertisers to evaluate notice and consent for the X Pixel under the ePrivacy rules.

Does the X Pixel set personalization_id on my domain?

No, X sets the personalization_id cookie on .twitter.com, never on your own domain. Firstly, the cookie arrives in the response of analytics.twitter.com. Secondly, the browser stores the cookie for the domain that sent the response. Thirdly, the X Pixel writes separate first-party cookies on your domain, such as _twclid.

What is the twclid parameter?

The twclid parameter is the click ID that X adds to the landing page URL of an X ad. The X Pixel "already automatically passes twclid from URL or first-party cookie", according to the X help on conversion tracking for websites, and the X Conversions API reads the same click ID from the twclid query string parameter.

Is the X Pixel the same as the Twitter Pixel?

Yes, the X Pixel is the former Twitter Pixel under the new name of the company. Firstly, the base code still loads uwt.js from static.ads-twitter.com. Secondly, the pixel still reports visits to analytics.twitter.com and t.co. Thirdly, the X help page on cookies still names Twitter in the descriptions of the cookies.