GA4 gtag

This is a reference of reverse-engineered /g/collect AKA gtag protocol.

info

3rd party references used:

• https://datajournal.datakyu.co/ga4-api-reference/
• https://www.thyngster.com/ga4-measurement-protocol-cheatsheet/
• https://medium.com/@mssvarma06/ga4-measurement-protocol-parameter-reference-b63d87bbe0eb

Method

POST

URL

https://www.google-analytics.com/g/collect

Query Parameters

Request Parameters

Parameter	Type	Description	Required
v	string	Protocol Version	Yes
tid	string	Tracking/Property ID - GA4 property identifier (e.g., G-XXXXXXXXXX)	Yes
gtm	string	GTM Has Info - indicates Google Tag Manager information	No
_p	int64	Random Page Load Hash - UTC Unix timestamp of the page load, in milliseconds	Yes
sr	string	Screen Resolution - e.g., "1920x1080"	No
ul	string	User Language - e.g., "en-us"	No
dh	string	Document Hostname - hostname of the page	No
cid	string	Client ID - unique identifier for the client	Yes
_s	int64	Hit Counter - indicates this is the nth hit/event sent in the current session	No
richsstsse	string	richsstsse parameter	No

Event Parameters

Parameter	Type	Description	Required
en	string	Event Name - name of the event being tracked	Yes
_et	int64	Engagement Time - time user engaged with the page in milliseconds	No
ep.*	string	Event Parameter (String) - custom event parameter	No
epn.*	number	Event Parameter (Number) - custom numeric event parameter	No
_c	bool	is Conversion - indicates if event is a conversion	No
_ee	bool	External Event - indicates if event is external	No

Shared Parameters

Parameter	Type	Description	Required
dl	string	Document Location - URL of the page	No
dt	string	Document Title - title of the page	No
dr	string	Document Referrer - referrer URL	No
_eu	string	Event Usage	No
_edid	string	Event Debug ID	No
_dbg	bool	is Debug - indicates debug mode	No
ir	bool	Ignore Referrer - if present and true, referrer is ignored. GA4 docs	No
tt	string	Traffic Type	No
gcs	string	Encodes the current google consent status in the format G<FunctionalStorageStatus><AdStorageStatus><AnalyticsStorageStatus>	No
gcu	string	Google Consent Update	No
gcut	string	Google Consent Update Type	No
gcd	string	Google Consent Default	No
_glv	bool	is Google Linker Valid	No

E-commerce Parameters

Parameter	Type	Description	Required
cu	string	Currency Code - e.g., "USD", "EUR"	No
ep.affiliation	string	Affiliation - store or affiliation	No
epn.value	number	Transaction Revenue - total transaction value	No
epn.tax	number	Transaction Tax	No
epn.shipping	number	Transaction Shipping	No
pr[0-9]{1,200}	object	Item - product/item data (supports up to 200 items)	No
pi	string	Promotion ID	No
pn	string	Promotion Name	No
cn	string	Creative Name	No
cs	string	Creative Slot	No
li	string	Location ID	No

Campaign Attribution Parameters

Parameter	Type	Description	Required
cm	string	Campaign Medium - e.g., "cpc", "email"	No
cs	string	Campaign Source - e.g., "google", "newsletter"	No
cn	string	Campaign Name	No
cc	string	Campaign Content	No
ct	string	Campaign Term	No
ccf	string	Campaign Creative Format	No
cmt	string	Campaign Marketing Tactic	No
_rnd	string	GCLID Deduper	No

User & Session Parameters

Parameter	Type	Description	Required
uid	string	User ID - optional user identifier	No
_fid	string	Firebase ID	No
sid	string	Session ID - unique session, assigned by the client when session starts, then propagated to every event	Yes
sct	int64	Session Count - number of sessions for the user	No
seg	int64	Session Engagement - engagement level of the session	No
up.*	string	User Property(ies) - custom user properties	No
upn.*	number	User Property Value - numeric user property	No
_fv	bool	First Visit - indicates first visit	No
_ss	bool	Session Start - indicates that this event starts the session. If present, always has value 1	No
_fplc	string	First Party Linker Cookie	No
nsi	string	New Session ID	No
gdid	string	Google Developer ID	No
_uc	string	User Country	No

Item Parameters

Used within item objects (pr[0-9]200):

Parameter	Type	Description	Required
id	string	Item ID	No
nm	string	Item Name	No
br	string	Item Brand	No
ca	string	Item Category Hierarchy 1	No
c2	string	Item Category Hierarchy 2	No
c3	string	Item Category Hierarchy 3	No
c4	string	Item Category Hierarchy 4	No
c5	string	Item Category Hierarchy 5	No
pr	number	Item Price	No
qt	number	Item Quantity	No
va	string	Item Variant	No
cp	string	Item Coupon	No
ds	number	Item Discount	No
ln	string	Item List Name	No
li	string	Item List ID	No
lp	number	Item List Position	No
af	string	Item Affiliation	No
lo	string	Item Location ID	No
cn	string	Item Creative Name	No
cs	string	Item Creative Slot	No
pi	string	Item Promotion ID	No
pn	string	Item Promotion Name	No

Client Parameters

Client Hints data:

Parameter	Type	Description	Required
uaa	string	User Agent Architecture - e.g., "x86"	No
uab	string	User Agent Bitness - e.g., "64"	No
uafvl	string	User Agent Full Version List	No
uamb	bool	User Agent Mobile - indicates if mobile	No
uam	string	User Agent Model - device model	No
uap	string	User Agent Platform - e.g., "Windows"	No
uapv	string	User Agent Platform Version	No