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What you are probably seeing
Your conversion volume in Ads Manager appears inflated compared to your actual sales data, causing you to misread campaign performance. The discrepancy becomes obvious when you compare the total revenue reported by Meta against your backend order records.
You notice that deduplication rates are low or missing in your event matching diagnostics. This suggests that Pixel and Conversions API events are not being linked correctly, leading to fragmented user journeys.
Why it happens
Meta duplicates events when the Pixel and Conversions API fire without a matching event ID. The system treats them as two separate actions because it lacks a unique identifier to link the browser and server signals.
Unmatched PII data prevents proper deduplication. If email and phone numbers are not hashed before being sent to Meta, the system cannot associate the server-side event with the browser-side event within the 48-hour window.
What changed recently
Step by step
1. Generate a unique event ID using a consistent format like the order ID prefixed with ‘purchase’ for every conversion.
2. Ensure this exact event ID is sent with both the Pixel event on the client side and the Conversions API payload on the server side.
3. Hash all email addresses and phone numbers using MD5 before including them in the Conversions API request.
4. Pass the fbp and fbc cookie values from the browser to your server so they can be included in the CAPI payload.
5. Check your Meta Events Manager deduplication settings to confirm that the events are successfully matching after these changes.
Ways to go further
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