The Conversions API sends events from your server so Meta can still see purchases when browser tracking falls short. Here is how to set it up without double counting.
Browser tracking alone misses conversions. Ad blockers, browser limits and consent choices all reduce what the Meta Pixel can see. The Conversions API (CAPI) sends events from your server to Meta, so the platform has a more complete picture to optimise on. For a peptide ecommerce store, the main risks are double counting and sending data you should not.
This guide complements our GA4 enhanced conversions guide and our Meta scaling guide.
Start with the standard commerce funnel and add nothing sensitive:
Use generic product identifiers. Avoid sending health claims, condition names or free-text fields in event parameters. If your business also provides care, read our guide to pixels and health data first.
If the Pixel and the Conversions API both send the same purchase, Meta needs a way to count it once. Meta's developer documentation recommends this method:
Meta states that when both keys arrive within 48 hours, the later event is discarded. If the two events do not differ meaningfully in content, Meta generally keeps the one it received first.
If you cannot send event IDs, Meta's documentation describes a fallback using event_name plus fbp and/or external_id sent consistently from both browser and server. It generally works only when the browser event arrives first, followed by the server event, and it does not deduplicate when all events come from one source. Use event IDs where you can.
| Route | Best for | Watch out for |
| Platform or partner integration | Stores on common ecommerce platforms | Check that deduplication is on and which events are sent |
| Server-side tag manager | Teams that want control over what is sent | Needs hosting and careful event ID handling |
| Direct API integration | Developers with custom stacks | You own hashing, retries and monitoring |
Better tracking is only useful if you judge results by profit. See our guide to MER, POAS and contribution margin, and keep the account healthy with the routine in our Account Quality guide.
It lets your server send events such as purchases directly to Meta, so the platform can measure and optimise even when browser tracking misses events.
Send the same event name and the same event ID from both sources to the same Pixel ID. Meta says that when both arrive within 48 hours, the later event is discarded.
Meta describes a fallback using event name plus fbp and/or external_id sent consistently from browser and server. It generally works only when the browser event arrives first.
No. Keep health claims, condition names and free-text fields out of event data, and review your setup with counsel if you provide care.
Make a test purchase, confirm it appears once in Events Manager with matching browser and server events, and compare Meta's counts with your store's.
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