Click ID

What is a click ID?

A click ID is an automatically generated tracking parameter that ad platforms append to destination URLs when a user clicks an ad. Each major platform uses its own click ID format:

• GCLID (Google Click Identifier) — Added by Google Ads
• FBCLID (Facebook Click Identifier) — Added by Meta (Facebook, Instagram)
• ttclid — Added by TikTok Ads
• msclkid — Added by Microsoft Advertising (Bing)
• li_fat_id — Added by LinkedIn Ads

When a user clicks an ad, the platform appends its click ID to the landing page URL — for example, https://example.com/pricing?gclid=abc123xyz. This identifier is then used to connect the ad click to any conversion that happens later on the advertiser's website.

Why they matter

Click IDs are the foundation of conversion attribution for paid advertising. Without them, ad platforms cannot determine which specific click led to a purchase, sign-up, or lead — and advertisers cannot measure return on ad spend.

• Conversion matching — Click IDs create a direct link between an ad interaction and a conversion event, enabling platforms to report which keywords, audiences, and creatives are driving results.
• Algorithmic optimization — Platforms like Google and Meta use conversion data tied to click IDs to train their bidding algorithms. Better conversion data means better automated bidding, which means lower cost per acquisition.
• Cross-session attribution — A visitor may click an ad today and convert three days later. The click ID, if preserved, bridges that gap.

The challenge is that click IDs are fragile. Browser privacy features strip or expire them. Client-side JavaScript may fail to capture them before navigation. Redirects can drop query parameters entirely. When click IDs are lost, conversions go unreported — and ad platform optimization suffers.

How they work

The lifecycle of a click ID follows a predictable pattern:

1. Generation — When a user clicks an ad, the ad platform generates a unique click ID and appends it to the destination URL as a query parameter.
2. Capture — The advertiser's tracking system reads the click ID from the URL when the landing page loads and stores it — typically in a browser cookie.
3. Persistence — The click ID must survive across page views and sessions until the visitor converts, which may be minutes or weeks later.
4. Conversion reporting — When a conversion event fires, the stored click ID is sent back to the ad platform (via a pixel, tag, or server-side API) to close the attribution loop.

Click ID vs. UTM parameters

Both are needed for comprehensive attribution. Click IDs feed conversion data back to ad platforms for optimization, while UTM parameters provide campaign context in your analytics tools.

How Ingest Labs handles click IDs

Ingest Labs captures GCLID, FBCLID, ttclid, and other click IDs server-side at the moment of first visit and stores them in a durable first-party cookie (MPID) that persists for up to two years. When the visitor converts — even days or weeks later — the original click ID is forwarded server-to-server to each ad platform's conversion API, ensuring accurate attribution and optimal algorithmic bidding without relying on browser-side pixels that ad blockers and ITP can disrupt.