Check 9 / 12 LOW impact In the full checklist
Server-side purchase deduplication check
What this check is
A purchase sent from both the browser and the server without a shared identifier is counted twice, which inflates the reported return on ad spend and misleads bidding.
How to implement it
Send a unique event id from both sources and let the platform deduplicate on it, verify the identifier survives the redirect flows in the checkout, and monitor the deduplication counters the platforms expose.
How to verify it
In the platform’s event diagnostics, check the purchase events for a matched deduplication rate near complete, and compare the platform’s order count with the store’s for the same day.
All 197 checks, one Google Sheet
This page is the summary. The full checklist carries the priority, the impact score and the tool link for every check — all 197 of them, across 14 categories, as a Google Sheet and CSV with lifetime updates.
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