Meta Pixel

Meta Pixel audit: is Facebook actually seeing your sales?

A Meta Pixel that loads isn't the same as a Pixel that reports conversions. duckmetric checks that Purchase, AddToCart and Lead fire with the right data, that CAPI deduplication is set up, and that you don't have duplicate pixels double-counting.

This audit is for teams that need proof, not guesses: whether tags fire on the real page, whether events contain the right parameters, and whether ad platforms receive the signal they need to optimise campaigns.

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What a Meta Pixel audit checks

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Standard events

PageView, ViewContent, AddToCart, InitiateCheckout, Purchase, Lead - which fire and where across your funnel.

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Event data quality

Purchase needs value, currency, content_ids / contents and content_type, or your catalog and value optimisation break.

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CAPI & deduplication

Is event_id present so the browser Pixel and Conversions API de-duplicate? No event_id usually means no CAPI - and iOS / ad-blocker losses.

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Duplicate pixels

Two Pixel inits or PageView firing twice (we've seen it live) double-count every conversion. We catch the duplicates.

The expensive Meta gap: the Pixel fires PageView so it looks "installed," but Purchase never reaches Meta. Meta then optimises your ads with no conversion signal at all - and your reported ROAS is fiction.

Common Meta Pixel problems we find

How to check your Meta Pixel yourself

A few minutes in the browser tells you whether Meta is really getting your conversions:

Filter Network for /tr/

Reload and act through the funnel. Each Pixel event is a request to facebook.com/tr/; the event name is the ev= parameter (e.g. ev=Purchase).

Check Purchase data

Confirm the Purchase request carries value, currency and content_ids - without them, catalog and value optimisation can't work.

Look for eventID

If the request has an eventID, a server-side CAPI event almost certainly exists for de-duplication. No eventID usually means browser-only - big iOS/ad-blocker losses.

Confirm in Events Manager

Use Meta Events Manager → Test Events to watch events arrive live, and check the "Deduplication" and "Event Match Quality" indicators.

Meta Pixel audit FAQ

How do I know if my Meta Pixel is tracking purchases?

In DevTools → Network filter for /tr/ and complete a test order. You should see a request with ev=Purchase carrying value, currency and content_ids. If PageView fires but Purchase never does, Meta is optimising with no conversion signal.

What is event_id and why does it matter?

The eventID lets Meta match a browser Pixel event with the same event sent server-side via the Conversions API, so it counts once instead of twice. Without it there's no de-duplication - and usually no CAPI, meaning conversions lost to iOS and ad blockers aren't recovered.

Why are my Meta conversions double-counted?

Usually a duplicate Pixel (two inits, or one hard-coded plus one in GTM) or PageView/Purchase firing twice. We've seen live sites fire Purchase twice. An audit spots the duplicate init and the double event.

Can you audit a Meta Pixel without Business Manager access?

Yes. The free scan reads the Pixel events straight from your URL in a real browser. Business Manager access only helps to confirm CAPI server events and match quality after the browser side is verified.

Audit your Meta Pixel free

See exactly which Meta events fire and whether CAPI is deduplicating. The full audit verifies Purchase end-to-end.

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