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

What the li_fat_id Cookie Does on Your Site

The li_fat_id cookie is a first-party advertising cookie that the LinkedIn Insight Tag sets to link a visit on your site to the LinkedIn ad click that brought the visitor. LinkedIn calls the li_fat_id value the "LinkedIn First-Party Ad Tracking ID". LinkedIn adds the ID to the landing page URL as a li_fat_id parameter every time a member clicks one of your LinkedIn ads. The Insight Tag stores the parameter in the li_fat_id cookie on your domain.

The LinkedIn Cookie Table describes the li_fat_id cookie as a "member indirect identifier for Members for conversion tracking, retargeting, analytics". LinkedIn uses the ID to credit a sign-up or a purchase on your site to the ad the member clicked, and to add the visitor to retargeting audiences.

Who Sets the li_fat_id Cookie

The LinkedIn Insight Tag sets the li_fat_id cookie, and only for visitors who arrive from a LinkedIn ad click. LinkedIn appends the li_fat_id parameter to your ad landing page URLs while Enhanced conversion tracking is on for the Insight Tag. LinkedIn turns the setting on by default for new Insight Tags, according to the LinkedIn developer documentation.

A visitor who comes from search, email, or a direct link gets no li_fat_id cookie, which explains why a cookie scanner finds the cookie on some visits only. Test the cookie by opening a landing page URL with a li_fat_id parameter, for example https://www.example.com/?li_fat_id=test, with the Insight Tag running.

Read how LinkedIn Corporation handles the data in the LinkedIn Insight Tag privacy policy, and sign the LinkedIn Data Processing Agreement 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 li_fat_id Cookie Need Consent?

Yes, the li_fat_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 LinkedIn Insight Tag, such as Enhanced conversion tracking.

The ePrivacy Directive requires consent before a site sets the li_fat_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 li_fat_id cookie.

The California Consumer Privacy Act (CCPA) sets no general opt-in requirement before a site sets the li_fat_id cookie. The CCPA treats the data the li_fat_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.

Send the li_fat_id value to the LinkedIn Conversions API only for visitors who accepted advertising cookies. The Conversions API matches the ID to a member profile on the server of LinkedIn, where no consent banner on your site blocks the request.

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 li_fat_id Cookie Until Visitors Accept

Block the li_fat_id cookie by holding back the LinkedIn Insight Tag until the visitor accepts advertising cookies. TermsFeed Free Cookie Consent and TermsFeed Privacy Consent place the LinkedIn Insight Tag in the advertising category. Check whether an exemption applies to your own use of the LinkedIn Insight Tag in the consent rules for the li_fat_id cookie.

The LinkedIn Insight Tag writes no li_fat_id cookie while the Insight Tag waits as a tagged script, even for a visitor whose landing page URL carries the li_fat_id parameter.

<script type="text/plain" data-cookie-consent="targeting">
  _linkedin_partner_id = "YOUR_PARTNER_ID";
  window._linkedin_data_partner_ids = window._linkedin_data_partner_ids || [];
  window._linkedin_data_partner_ids.push(_linkedin_partner_id);
</script>
<script type="text/plain" data-cookie-consent="targeting">
  (function (l) {
    if (!l) {
      window.lintrk = function (a, b) { window.lintrk.q.push([a, b]); };
      window.lintrk.q = [];
    }
    var s = document.getElementsByTagName("script")[0];
    var b = document.createElement("script");
    b.type = "text/javascript";
    b.async = true;
    b.src = "https://snap.licdn.com/li.lms-analytics/insight.min.js";
    s.parentNode.insertBefore(b, s);
  })(window.lintrk);
</script>

Stop the li_fat_id Cookie in LinkedIn Campaign Manager

Turn off Enhanced conversion tracking for the Insight Tag in LinkedIn Campaign Manager to stop the li_fat_id parameter, and with the parameter the li_fat_id cookie. LinkedIn appends the parameter to ad landing page URLs only while Enhanced conversion tracking is on, according to the LinkedIn developer documentation.

The setting stops the first-party cookie only. The Insight Tag still sends every visit to px.ads.linkedin.com and still triggers the LinkedIn cookies on .linkedin.com, so the Insight Tag needs consent with Enhanced conversion tracking off as well.

How to Verify That the li_fat_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 li_fat_id cookie must not appear in the list until you accept advertising cookies.

How Long the li_fat_id Cookie Lasts

The li_fat_id cookie lasts 30 days. Safari caps the cookies that JavaScript sets at 7 days of Safari use without an interaction with your site, according to the WebKit team behind Safari.

The li_fat_id cookie lasts 30 days from the most recent ad click, so a new click on a LinkedIn ad starts the 30 days again. Page views without an ad click do not extend the lifetime, according to the LinkedIn developer documentation.

LinkedIn keeps the link between a li_fat_id value and the LinkedIn member profile for 365 days (12 months). The ID therefore still matches the member through the LinkedIn Conversions API after the cookie has expired.

Cookies That Work Together With li_fat_id

The LinkedIn Insight Tag sets 14 other cookies next to the li_fat_id cookie in its current setup.

Scripts and Requests of the LinkedIn Insight Tag That Come With the li_fat_id Cookie

The catalog lists 3 scripts, pixels, and data endpoints of the LinkedIn Insight Tag, which a cookie scanner or the Network tab of Chrome DevTools shows next to the li_fat_id cookie. Block the main script, and the requests in the table stop with the main script.

li_fat_id Cookie FAQs

Is li_fat_id a necessary cookie?

No, the li_fat_id cookie is not a strictly necessary cookie. Firstly, your site works the same for a visitor who refuses the li_fat_id cookie. Secondly, LinkedIn uses the cookie for conversion tracking, retargeting, and analytics, purposes the ePrivacy Directive exemption does not cover. Thirdly, the cookie serves your LinkedIn advertising, not a service the visitor asked for.

Why does li_fat_id appear only on some visits?

The li_fat_id cookie appears only after a visitor clicks a LinkedIn ad, because LinkedIn passes the ID in the li_fat_id parameter of the ad landing page URL. The Insight Tag turns the parameter into a cookie on your domain. Visitors from every other source get no li_fat_id cookie.

Does the li_fat_id cookie contain personal data?

Yes, the li_fat_id cookie holds personal data under the GDPR. Firstly, LinkedIn calls the value a "member indirect identifier". Secondly, LinkedIn links the value to the LinkedIn member profile for 365 days. Thirdly, Recital 30 of the GDPR names cookie identifiers among the online identifiers that make a person identifiable.

What is the difference between li_fat_id and li_giant?

The li_fat_id cookie identifies a single LinkedIn member for 30 days, and the li_giant cookie identifies a group of LinkedIn members for 7 days. LinkedIn uses both cookies for conversion tracking, according to the LinkedIn Cookie Table.

How do I send li_fat_id to the LinkedIn Conversions API?

Read the li_fat_id cookie with JavaScript and pass the value as a hidden field when the visitor submits a form. Send the value as LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID with the conversion event, according to the LinkedIn developer documentation. Read the cookie only for visitors who accepted advertising cookies.