Is there any documentation about cfz_

Is there any documentation about cfz_google-analytics_v4 cookie?
4 Replies
Mackenly
Mackenly5w ago
What questions do you have? I've worked with it some before (adding compatbility for a integration that needed to pulled data from "Google's" cookies where I mocked them using data pulled from the Zaraz cookie)
taf2
taf2OP5w ago
i see some of the ga4 cookie values stored in cfz_google-analyticsv4 and decoding it allows me to see what appears to be the client id and session id but it looks like the measurement id is missing... ga<ContainerId> is missing also i am guessing that the client id is the uuid value... just i guess wondering if cloudflare has the components of the cookie document some where it would be very helpful For example, i can see this data from the cookie:
{
"egnm_engagementDuration": {"v": "0", "e": 1772561008328},
"egnm_engagementStart": {"v": "1741025008328", "e": 1772561008328},
"egnm_counter": {"v": "2", "e": 1772561008328},
"egnm_session_counter": {"v": "2", "e": 1772561008328},
"egnm_ga4": {"v": "3ba93466-8729-4e58-96ff-09d2c6233ca2", "e": 1772561008328},
"egnm__z_ga_audiences": {"v": "3ba93466-8729-4e58-96ff-09d2c6233ca2", "e": 1772556765275},
"egnm_let": {"v": "1741025008328", "e": 1772561008328},
"egnm_ga4sid": {"v": "417825486", "e": 1741026808328}
}
{
"egnm_engagementDuration": {"v": "0", "e": 1772561008328},
"egnm_engagementStart": {"v": "1741025008328", "e": 1772561008328},
"egnm_counter": {"v": "2", "e": 1772561008328},
"egnm_session_counter": {"v": "2", "e": 1772561008328},
"egnm_ga4": {"v": "3ba93466-8729-4e58-96ff-09d2c6233ca2", "e": 1772561008328},
"egnm__z_ga_audiences": {"v": "3ba93466-8729-4e58-96ff-09d2c6233ca2", "e": 1772556765275},
"egnm_let": {"v": "1741025008328", "e": 1772561008328},
"egnm_ga4sid": {"v": "417825486", "e": 1741026808328}
}
but it's unclear what each of the keys within the encoded json structure represent or how they specifically would map to google analytics api i am assuming egnm_ga4.v is a custom client_id
Mackenly
Mackenly5w ago
I found info through looking at the implementation here: https://github.com/managed-components/google-analytics-4 I don't think measurement ID is stored there. My implementation pulls it out of a zaraz variable (that's also used to set it in the GA4 tool) These are two resources I referenced in my notes: - https://crossmasters.com/en/blog/ga-cookies-explained/ - https://www.bbccss.com/explanation-of-cookie-values-used-by-ga4.html Ran your cookie through chatgpt with my code and these are the labels (looks mostly right): - egnm_engagementDuration: The duration of user engagement (in milliseconds). A value of "0" means no active engagement was recorded. - egnm_engagementStart: The timestamp (in epoch format) when the user's engagement began. - egnm_counter: A general counter that likely tracks the number of events or interactions. - egnm_session_counter: The count of sessions the user has initiated on the site. - egnm_ga4: A unique GA4 client identifier used for tracking and analytics. - egnm__z_ga_audiences: An identifier for audience segmentation that matches the GA4 client ID. - egnm_let: The timestamp of the last recorded event. - egnm_ga4sid: The GA4 session ID, which uniquely identifies the current session.
taf2
taf2OP5w ago
awesome yeah that matches what i got here as well that link via github is super helpful i did not realize the zaraz code was open like this

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