Glossary

Click ID

A click ID is a unique identifier the tracking system generates for every individual click. It travels to the landing page as a URL parameter, gets stored by the advertiser, and comes back in the conversion postback — tying each conversion to the exact click, source, and creative that produced it.

How it works

On every click the tracker mints a fresh ID and appends it to the destination URL — for example ?click_id=7291834612345678. Because the ID is unique per click, the eventual postback resolves to one specific row in the click log, and everything known about that row — campaign, zone, sub IDs, geo, device, timestamp — is inherited by the conversion.

When traffic passes through multiple systems (an affiliate's tracker, then a network's platform), each system issues its own click ID and stores the upstream one, so postbacks can be chained back hop by hop. In Affset this incoming identifier is the source_click_id, echoed back to the traffic source via the {source_click_id} macro.

Why it matters

Click-ID attribution is what makes performance marketing auditable: no shared cookies, no probabilistic matching — a conversion either carries a valid click ID or it does not. Lost or truncated click IDs are the single most common cause of "missing conversions" disputes.

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