Click ID
A click ID is a unique identifier assigned to each ad click so a later conversion can be matched back to the exact click that caused it.
A click ID is a unique identifier generated for every individual ad click and passed through the URL, allowing an ad network or tracker to connect that click to whatever happens afterward, most importantly, a conversion. It is the thread that stitches a click to its outcome.
How it works#
When a user clicks an ad, the network creates a click ID (Taboola's cid, Outbrain's ob_click_id, Google's gclid, and so on) and appends it as a URL parameter on the way to the Landing Page. As the click moves through a Redirect Chain, the ID is carried forward. The advertiser stores it, and when a conversion fires, the click ID is sent back, usually via a Postback URL, so the network can match outcome to source.
Why it matters#
The click ID is the backbone of accurate attribution. Without it, a network knows a conversion occurred but not which click, creative, or publisher earned it. It enables granular Click Tracking, powers conversion matching across domains, and lets optimization algorithms learn which placements convert. For competitive researchers, click IDs in captured ad URLs also reveal which tracking platform and network sit behind a campaign.
Related terms: Click Tracking, Postback URL, and Redirect Chain.
