What is Conversion Deduplication?

Conversion deduplication prevents counting the same goal action twice when it is reported through multiple channels: browser pixel and Conversion API, duplicate network postbacks, or repeated CRM sends.

Without dedup, ad account metrics inflate, algorithm training skews (Meta/Google optimize on phantom events), and payout disputes arise when two systems credit the same action.

Key scenarios

Pixel + CAPI — shared event_id in Meta Events Manager.
Repeat postback — tracker ignores duplicate by click ID + transaction ID.
Cross-device — harder; time windows and unique order IDs are common.

Implementation

Ad platforms document dedup fields (Meta: event_id, event_name, fbp). Trackers can accept one conversion per click or per external ID. Nutra advertisers may dedup leads by phone — approval rate drops but fraud falls.

For media buyers

When sending S2S to ads, do not fire both pixel and postback for the same event without dedup. Log order external_id in the postback URL. If tracker vs. Meta counts differ, check duplicates in Events Manager → Test Events first.