What is the Meta (Facebook) Pixel?
The Meta pixel is Facebook and Instagram's tracking tag. It sits on your website and reports what visitors do, page views, add-to-carts, purchases, so Meta can measure and optimise your ads.
What it does
The pixel ties actions on your site back to the ad someone clicked. That powers three things: measuring which ads drive sales, building retargeting audiences, and feeding Meta's optimisation so it finds more buyers. It is the same idea as any tracking pixel, just Meta's version.
Why it quietly undercounts now
Since Apple's iOS privacy changes, a large share of users opt out of app tracking, so the browser-based pixel simply cannot see many conversions. On top of that, consent, ad blockers and cookie limits all chip away at it. The result: Meta often reports fewer sales than you really got, and its optimisation suffers.
The fix: the Conversions API
The current best practice is to pair the pixel with the Conversions API (CAPI), which sends conversions server-to-server instead of relying only on the browser. Done with proper event deduplication, it recovers a big chunk of the conversions the pixel alone now misses. If Meta and your shop never agree on numbers, this is usually why.
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