How duplicate conversions are prevented
Trackdesk uses the External ID parameter to prevent duplicate conversions.
This ensures that repeated events, such as page reloads or duplicate requests, do not create multiple conversions for the same transaction.
How deduplication works
Deduplication is based on a combination of:
Conversion Type
External ID
This means that:
The same External ID can be used across different Conversion Types
Only one conversion per Conversion Type can have the same External ID (for Network accounts, per Conversion Type and Revenue Origin)
If a conversion is sent with a combination that already exists, Trackdesk does not create a second conversion and records the attempt in the Conversion error log.
Example: page refresh scenario
If you pass an order ID as the External ID:
A user completes a purchase → conversion is created
The user refreshes the thank-you page → same External ID is sent again
Trackdesk detects the duplicate → no additional conversion is created
This prevents duplicate tracking caused by repeated events.
What is the difference between External CID and External ID?
External CID
Used for click identification and pairing
Similar to Trackdesk CID, but provided by your system
Can be set via script or API
Allows conversions to be attributed using your own identifier, on top of the regular CID
External ID
Used for conversion identification and deduplication
Should be unique per conversion (within the deduplication scope)
Commonly set as:
Order ID
Transaction ID
Payment ID
Also used when updating conversions via API
Summary
External ID prevents duplicate conversions
Deduplication is based on:
Conversion Type + External ID
(+ Revenue Origin ID for Network clients)
External CID is used for tracking/attribution, not deduplication