Meta Pixel and Conversions API Deduplication Issues on Shopify

[alexyou]

Hello Shopify Community,

In December 2024, I integrated Meta Pixel with my Shopify store using Meta’s official app, and everything functioned smoothly. I have not made any special or unusual changes to my Shopify setup. However, this afternoon, I received the following error message:

“Your pixel is receiving identical Purchase events from your pixel code and the Conversions API, but they are not deduplicated correctly. This may cause over-reporting of conversions, as your ad set is optimizing for Purchase events.”

In the Diagnostics section, I encountered these specific errors:​

• Purchase Event Missing Deduplication Parameter​
• AddPaymentInfo Event Missing Deduplication Parameter​
• InitiateCheckout Event Missing Deduplication Parameter​
• Search Event Missing Deduplication Parameter​
• Web - Fix unmatched content IDs

​After conducting thorough research, I understand that adding an event_id parameter to both the pixel and Conversions API events is crucial for proper deduplication. However, I’m uncertain about the exact steps to implement this in my Shopify setup.

Could anyone provide detailed guidance or best practices on how to add the event_id parameter to ensure accurate event tracking and resolve these deduplication errors?

Thank you in advance for your assistance!

​

[fronus]

Any solution for this?

[EnricoForte]

The official Meta Shopify app should already generate matching event_ids for the browser pixel and CAPI events. Those deduplication warnings often appear when a second source is sending the same events without the matching parameter, usually a hardcoded Meta pixel snippet left in theme.liquid or a third-party tracker such as Stape, Elevar or Trackify running in parallel. The unmatched content IDs warning also points to product data being passed in different formats between paths. That can double-count purchases and inflate reported ROAS, so I would not try to fix this by manually adding event_id first. Check Meta Events Manager for multiple origins on the same Purchase events, then remove the conflicting source and re-test.