How Reddit event deduplication works
One conversion sent twice must count once. This guide makes Conversion IDs consistent across every channel.
When the same conversion travels through both Pixel and CAPI, Reddit merges the pair only if both carry a consistent Conversion ID. Without it, reports double-count, ROAS inflates, and bidders learn from fiction.
The ID contract#
Every conversion event gets a unique ID generated at the transaction: order IDs for purchases, lead IDs for forms, signup IDs for accounts. Both Pixel and CAPI transmit the identical value for the identical event. Reddit Help states the consistency requirement plainly. Contract: linking standard events.
Implementation order#
Generate IDs server-side at transaction time, pass them into the data layer, fire Pixel with the ID, fire CAPI with the ID. Client-generated IDs risk mismatch across channels; server truth keeps both honest. Event catalogue: standard events.
Testing dedup#
Fire test transactions through both channels and confirm single counting in Events Manager before scaling. Then spot-check weekly: match rate drops and sudden ROAS jumps both signal dedup decay. Dedup detail: event deduplication help.
Catalogue IDs too#
Product IDs in catalogues must match the IDs in Pixel and CAPI events for product-level measurement and DPA optimisation. Two ID contracts, one discipline: identifiers agree everywhere or measurement quietly breaks. Catalogue health: catalogue health.
The cost of skipping#
Doubled conversions halve apparent CPA, which invites budget increases into phantom efficiency. When dedup later gets fixed, performance appears to collapse overnight. Fix it before spending, not after celebrating. Optimisation stakes: Pixel setup.
Putting dedup into practice#
Add dedup verification to the launch checklist for every conversion campaign: test transactions through both channels, single counting confirmed, then spend. Retroactively audit live accounts this week; long-running double-counting corrupts every historical comparison it touched.
Alert on match-rate drops and sudden ROAS jumps as dedup-decay smoke signals. Smoke response: Pixel setup and reporting latency.
Frequently asked questions#
What is event deduplication?
Merging identical conversions sent through both Pixel and CAPI into a single counted event.
How does Reddit dedup events?
Through consistent Conversion IDs: identical values on both channels merge, mismatches double-count.
Where should IDs be generated?
Server-side at transaction time, passed into the data layer for both channels.
How is dedup tested?
Fire test transactions through both paths and confirm single counting in Events Manager.
Do catalogue IDs matter too?
Yes. Catalogue product IDs must match event product IDs for product measurement and DPA.
What belongs on the launch checklist?
Dual-channel test transactions with single counting confirmed before spend.
Read more on this topic#
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