What Are fbp and fbc? (And fbclid) in Meta CAPI

What are fbp and fbc? fbp and fbc are two Meta identifiers that help tie a conversion event to a specific person and a specific ad. fbp identifies the browser; fbc identifies the click on the ad. Both are sent in the user_data of a CAPI call, and both weigh on the Event Match Quality score.

fbp: the Pixel cookie

fbp is the value of the _fbp cookie, which the Meta Pixel writes in the browser of whoever visits the page. It identifies that browser, not the ad. Its format is fb.1.<timestamp>.<random number>. If the Pixel hasn’t run before you read the cookie, fbp simply doesn’t exist yet.

fbc: the ad click

fbc is the value of the _fbc cookie, which links the visitor to a click on an ad. When someone clicks a Meta ad, Meta adds the fbclid parameter to the destination URL. fbc is built from it, in the format fb.1.<click timestamp>.<fbclid>. No fbclid in the URL means no fbc to send.

What about fbclid?

fbclid is the click parameter in the URL. It’s the raw material for fbc: it has to be read from the URL and turned into fbc before the person leaves the page. If the page ignores the parameter, the click information is lost.

Why they matter in CAPI

With CAPI, the event leaves from a server, not from the browser. Without these identifiers, Meta has fewer clues to match the event to the person who clicked. Sending fbp and fbc together with the IP address and user agent usually raises the event’s score. When the Pixel and CAPI send the same event, a shared event_id prevents double counting (see event deduplication).

In a Telegram funnel

fbp and fbclid only exist while the person is on the bridge page, before they go to Telegram. Inside the app there’s no cookie and no ad URL. That’s why, if you build your own tracking, you have to capture them there, together with the record of the click.

With Track4you, that’s already handled. The script on the page records the visit and the click with their origin, and Track4you sends the IP address, user agent and fbp/fbc (when available) to Meta along with the events. That’s what feeds the Event Match Quality of enter_channel and the other funnel events. The postbacks Track4you sends to your CRM or automation also carry fbp and fbc when available, which is useful if your own system sends events to Meta too.

See the step-by-step in how to improve Event Match Quality and the guide to tracking Telegram conversions.