gbraid and wbraid
Click identifiers for iOS journeys where a GCLID is not available. wbraid covers an app-to-web click, gbraid a web-to-app one. They are not interchangeable with each other or with GCLID.
Why it matters
An implementation that only reads gclid quietly loses a share of iOS traffic, and iOS traffic is disproportionately the expensive kind in a lot of lead-gen categories.
What goes wrong
The practical rule is to read and store whichever of the three arrives rather than picking one. Google's API documentation recommends sending both a click identifier and user-provided data when both are available, and some conversions can legitimately carry both gclid and gbraid.
How to check it on your own account
Search your CRM for leads carrying gbraid or wbraid values. If the count is zero and you run any iOS traffic, your capture is reading gclid only.
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Measure this on your own data
The diagnostic reads a CRM export in your browser and reports your volume, your match rate and the spread between your leads against the thresholds in this glossary. Nothing is uploaded and no account is needed.