# li_fat_id — LinkedIn Ads' email-based click ID

- Canonical: https://linkclean.app/trackers/li-fat-id/
- Updated: 2026-07-20
- Author: Ken Tominaga (https://ken0nek.com)
- Get the app: https://apps.apple.com/us/app/linkclean/id6758604043

Parameter: `li_fat_id` · Category: Ad-click identifiers · Vendor: LinkedIn Ads

> li_fat_id is **LinkedIn's First-party Ad Tracking identifier** — “fat” = First-party Ad Tracking. Tied to the LinkedIn member who clicked, via the email address they registered with. Higher privacy stakes than most ad-click IDs.

## Why li_fat_id is different

Most ad-network click IDs (fbclid, gclid, msclkid, ttclid) are tied to a *session* on the ad network's side — joinable to your account on their books, but not literally your email address.

li_fat_id is unusual: it's tied to LinkedIn's first-party identity record for the member, which is keyed to their email address. LinkedIn pioneered this so it could keep attribution working across browsers that block third-party cookies — but the result is an ad-click ID more tightly bound to a named-individual identity than the rest.

Forwarding li_fat_id leaks an identifier joined directly to the original member's LinkedIn email. The blast radius is closer to Mailchimp's mc_eid than to fbclid.

## How LinkClean removes it

li_fat_id is in LinkedIn's reference catalog and ships on by default for LinkedIn ad-link cleaning. LinkClean also strips `rcm` (LinkedIn's share/recommendation token) host-scoped to linkedin.com.

## Example

Looks like this in a URL: `https://example.com/landing?li_fat_id=2a1b3c4d-5e6f-7890-abcd-ef1234567890`

After LinkClean: `https://example.com/landing`

## Frequently asked

**What does “FAT” stand for in li_fat_id?**

First-party Ad Tracking. LinkedIn's name for their cookie-independent click-attribution system, introduced to keep conversion measurement working under Safari's Intelligent Tracking Prevention and Firefox's tracking protections.

**Is li_fat_id more personal than fbclid?**

Yes. It's bound to the LinkedIn member's email-address identity on LinkedIn's side, not just a session cookie. Forwarding it leaks an identifier closer to an email address than to a fbclid-style click session.

**Does LinkedIn also use rcm?**

Yes — rcm is LinkedIn's share/recommendation token (a different identifier from li_fat_id). LinkClean strips it too, host-scoped to linkedin.com.


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