Meta pixel

The Meta pixel (formerly Facebook pixel) is Meta's JavaScript snippet that reports website events (PageView, Purchase, Lead, AddToCart) from the visitor's browser to Meta. Those events power ad measurement, audience building, and delivery optimization. Your pixel ID lives in Meta Events Manager, under Data sources.

#The browser half of a two-transport system

The pixel is Meta's browser-side collector, and it no longer works alone. It sets the _fbp cookie (and captures the fbclid click ID into _fbc) to connect events back to ad clicks. Those are exactly the mechanics that ad blockers, Safari's seven-day cookie caps, ATT, and consent banners have been eroding for years. Meta's answer is redundancy: the Conversions API sends the same events server-side, and Events Manager deduplicates the two streams by shared event_id. So "the pixel" today is one half of a pair: running it alone means undercounting, and running both without dedup means double-counting. Meta's shifting vocabulary (pixel, dataset, CAPI) describes containers around that same event stream, not different products.

Buron runs its first-party pixel alongside Meta's stack and monitors the dedup between browser and server streams, so drift shows up as a finding rather than a quarter of inflated ROAS.

What the Meta pixel still sees today (and the honest list of what it can't see anymore) is the full entity page: The Meta Pixel: what it is, what it sees, where to find your ID. The pixel-vs-CAPI decision is Conversions API vs the Meta Pixel: what actually changes, the generic mechanism is Tracking pixel, and Conversion tracking & signal quality maps the wider territory.