Tracking

li_fat_id

LinkedIn First-Party Ads Tracking ID

In short

The li_fat_id is the click ID of LinkedIn Ads. LinkedIn appends it to the landing page URL on an ad click so conversions sent through the Conversions API can be matched to the click and the LinkedIn member.

Also known as: LinkedIn Click ID

The li_fat_id (LinkedIn First-Party Ads Tracking ID) is LinkedIn's click ID, comparable to Google's gclid or Meta's fbclid. It is added to the landing page URL as a parameter after a click on a LinkedIn ad, provided first-party cookie tracking is enabled in Campaign Manager.

How the li_fat_id is used

  1. Someone clicks your LinkedIn ad, and the li_fat_id is added to the URL.
  2. Your tracking stores the ID during the visit and links it to the lead.
  3. When a conversion happens, the li_fat_id is sent to LinkedIn through the LinkedIn Conversions API as the identifier LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID, ideally together with the hashed email address.

According to LinkedIn, the mapping of a li_fat_id to a member profile is stored for 365 days, even after the browser cookie has expired (LinkedIn Conversions FAQ).

The li_fat_id in lead generation

In B2B, many leads sign up with a work address while their LinkedIn profile uses a personal email address. Then the hashed email doesn't match, but the li_fat_id does. LeadMetrics captures the li_fat_id during the visit, links it to the lead and sends it to LinkedIn with leads and deals through the Conversion API.

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Frequently asked questions

Not necessarily. LinkedIn also accepts hashed email addresses and other identifiers. But the li_fat_id improves matching, especially when someone signs up with a personal email address that isn't linked to their LinkedIn profile.

Guides on this topic

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Related terms

All terms

gclid · Google Click Identifier

The gclid (Google Click Identifier) is a unique ID that Google Ads appends to the landing page URL on every ad click so conversions can be tied to that click.

fbclid · Facebook Click Identifier

The fbclid (Facebook Click Identifier) is an ID Meta appends to links from Facebook and Instagram so conversions can be attributed to the original click.

ttclid · TikTok Click ID

The ttclid (TikTok Click ID) is an identifier TikTok appends to the landing page URL on an ad click. TikTok uses it to attribute later conversions to that click.

Conversion API · CAPI

A Conversion API (CAPI) is an interface that sends conversions directly from server to server to ad platforms like Meta or Google, without the browser.

First-Party Cookies

First-party cookies are set by the domain you are currently visiting. They store things like logins, shopping carts or tracking IDs for that same website.

Client-Side Tracking

Client-side tracking captures user actions with JavaScript directly in the browser and sends them from there to analytics and ad platforms.