What are fbc and fbp?
fbc is Meta's click id built from the fbclid on an ad click; fbp is Meta's browser id. Both help match events to people.
fbc is Meta's click id, built from the fbclid parameter Meta adds to ad clicks, in the form fb.1.timestamp.fbclid. fbp is Meta's browser id, stored in the _fbp cookie. Sending both with Conversions API events helps Meta match a purchase to the ad click and the person.
Store fbc in a first-party cookie on landing so later events, including the purchase, still carry it. Meta suggests keeping it for 90 days.
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