What is a click ID?

What a click ID is

When someone clicks an ad, the platform redirects them to your page and appends a long, unique value: ?gclid=Cj0KCQ…. The value means nothing on its own, but the ad platform can look it up to find the campaign, ad group, keyword and time of that click.

That makes click IDs useful twice. Your analytics can say "this visit came from a Google ad" even when there is no referrer and no UTM tag. And when the visitor later signs up or buys, you can send the click ID back to the ad platform as a conversion, which is what its bidding algorithms learn from.

Common click IDs

• gclid, wbraid, gbraid — Google Ads (the last two are used on iOS traffic); dclid — Google display.
• fbclid — Meta (Facebook and Instagram). Note that Meta also adds it to some non-ad outbound links.
• ttclid — TikTok; msclkid — Microsoft Ads; twclid — X; li_fat_id — LinkedIn.
• ScCid — Snapchat; epik — Pinterest; rdt_cid — Reddit; yclid — Yandex.
• In China: clickid — Ocean Engine (Douyin, Toutiao); bd_vid — Baidu; gdt_vid / qz_gdt — Tencent Ads; callback — Kuaishou.

Click IDs versus UTM tags

UTM tags are written by you, readable, and work on any link. Click IDs are added by the platform, unreadable, and only exist on ad clicks. They solve different problems:

• A missing or mistyped UTM tag silently moves ad traffic into Direct or Other. A click ID is added to every click automatically.
• UTM tags carry your campaign names into reports. Click IDs only say which platform, unless you query the platform.
• Only click IDs can be sent back to the ad platform for conversion matching.

For paid campaigns, keep auto-tagging on and add UTM tags as well.

How TapCub uses click IDs

TapCub recognises 18 click-ID parameters from 14 ad platforms, including all of those listed above. When a landing URL has one, the session is classified as paid search, paid social or display before any other rule runs, so ad traffic without a referrer is not counted as direct. (fbclid alone counts as social, because Meta also adds it to organic shares.)

The value is stored as a hash for reports and deduplication, and in encrypted form for one purpose: conversion postback, where TapCub sends sign-ups, leads or purchases back to the ad platform keyed by the click ID so its bidding can learn. The payload contains only the click ID, the platform event, the time and the value.

Common mistakes

• Stripping query strings. Redirects, URL shorteners and some caching layers drop parameters. If paid traffic shows up as direct, check the landing URL first.
• Turning off auto-tagging. Without it, attribution relies entirely on manual UTM tags.
• Reading every fbclid as an ad. Meta adds it to ordinary outbound links too; only treat it as paid when combined with a paid medium.
• Logging raw click IDs everywhere. They identify a click by one person. Store them only where needed for conversion matching.

Related guides: Lead Tracking and Conversion Tracking.