This guide gives you context around
_fbp. These 2 parameters represent browser cookie values and can be sent with your server events. See About Cookie Settings For Your Facebook Pixel.
We recommend that you always send
_fbp browser cookie values in the
fbp event parameters, respectively, when available. These values are subject to change over multiple browser sessions, so we recommend refreshing a user’s profile with the latest value whenever possible.
When the Facebook pixel is installed on a website, and the pixel uses first-party cookies, the pixel automatically saves a unique identifier to an
_fbp cookie for the website domain if one does not already exist.
When a user clicks on an ad on Facebook, the link sometimes includes a
fbclid query parameter. When the user lands on the target website, if the website has a Facebook pixel that uses first-party cookies, the pixel automatically saves the
fbclid query parameter to an
_fbc cookie for that website domain. See About Cookie Settings For Your Facebook Pixel for information on first-party cookie settings.
_fbc browser cookie is not available, either because there is no Facebook pixel running on the website or because first-party cookies are turned off, it is still possible to send the
fbc event parameter if an
fbclid query parameter is in the URL of the current page request.
fbc event parameter value must be of the form version.subdomainIndex.creationTime.fbclid, where:
versionis always this prefix:
subdomainIndexis which domain the cookie is defined on ('com' = 0, 'facebook.com' = 1, 'www.facebook.com' = 2). If you’re generating this field on a server, and not saving an
_fbccookie, use the value 1.
creationTimeis the UNIX time since epoch in seconds when the _fbc cookie was saved. If you don't save the _fbc cookie, use the timestamp when you first observed or received this fbclid value.
fbclidis the value for the
fbclidquery parameter in the page URL.
Here’s an example of what the
fbc value could look like (note that the
fbclid portion is invalid):