A click ID is a unique serial number stamped on every single click. When a sale or sign-up happens later, that number comes back with it, so everyone can see exactly which click, and therefore which ad and which affiliate, produced the result.
A click ID is a unique string generated for each click and carried through every hop of the funnel so that a later conversion can be matched to it. In affiliate tracking there are usually several at once: the affiliate’s tracker mints its own ID, the network generates another when the click hits its tracking link, and the advertiser stores the network’s ID with the order. Scaleo, for example, creates a 32-character click_id for every click and accepts the affiliate’s own value in aff_click_id. When the conversion happens, each system receives the ID it issued in a postback and looks up the click stored under it.
Ad platforms use the same idea for their own attribution. Google Ads auto-tagging appends gclid to the landing URL, Meta appends fbclid, Microsoft Advertising msclkid and TikTok ttclid. These values let the platform connect a later conversion upload or server event to the ad that was clicked, which is also why landing pages must never strip unknown query parameters from the URL.
Click IDs are fragile in transit. They disappear when a redirect drops the query string, when a prelander links to the offer without passing the value on, when it is sent under the wrong parameter name, or when the browser removes it: since iOS 17, Safari’s Link Tracking Protection strips known identifiers such as gclid and fbclid from links opened in Mail, Messages and Private Browsing, while leaving UTM tags intact. A lost ID does not stop the sale; it only stops the credit.
Good practice is short. Generate one ID per click on the server side of the tracker, pass it to the network in the dedicated click-ID parameter rather than a generic sub-ID field, confirm that the network returns it through the right postback macro, and test one click from ad to conversion before spending. When reports diverge, the first thing to count is how many conversions arrived with an empty or unknown click ID.
A visitor clicks a native ad, reads a prelander and signs up for a VPN trial. Here is the chain of identifiers that makes the sign-up count.
| Step | What happens | ID in play |
|---|---|---|
| 1 | Native source sends the click to the tracker | source macro, e.g. n-88412 |
| 2 | Tracker logs the click and shows the prelander | tracker ID 7f3a9c… |
| 3 | Prelander button opens the network tracking link | aff_click_id=7f3a9c… |
| 4 | Network logs its own click, redirects to the offer | network click_id (32 characters) |
| 5 | User signs up; advertiser posts back to the network | network click_id |
| 6 | Network posts back to the tracker | 7f3a9c… returned from aff_click_id |
| 7 | Tracker reports the conversion to the native source | n-88412 |
If step 3 loses the value, for instance because the prelander button was hard-coded with the plain tracking link, the network still records and pays the conversion, but the tracker receives a postback with an empty ID and the native source never learns which placement worked. Optimisation then runs on guesswork. IDs are illustrative.
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A unique value created for each click and passed along to the offer, so the conversion can be matched back to that exact click and, through it, to the affiliate, source and creative.
A click ID is unique to one click and identifies one visit. Sub IDs are labels you choose, such as source or campaign, that repeat across many clicks and group them in reports.
Usually a redirect or hard-coded link dropped the parameter, it was sent under the wrong name, or the postback macro is not mapped. On some iOS surfaces known identifiers are also stripped.
Click identifiers that Google Ads and Meta add to ad URLs automatically, so their systems can tie later conversions back to the ad click that produced them.
References are listed as plain text on purpose; look them up by title and publisher. Updated: 2026-10-09.
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