About GA4 Configuration fields

https://developers.google.com/analytics/devguides/collection/ga4/reference/config

GA4 has its few

client_id

stored as part of first-party analytics cookie for 2 year, use for identify each user.

gtag('set', 'client_id', '123456');
gtag('event', 'test_gtag_set', { test_id: 'client_id'});

The collect?v=2 request's query string key will be cid. Big Query column is user_pseudo_id, also the cookie _ga value will be update to GA.1.1.123456. Update this value, the subsequence request will always set the same value since cookie updated.

language

by default using the window object's nagigator.language's value.

gtag('set', 'language', 'en-ca');
gtag('event', 'test_gtag_set', { test_id: 'language'});

The collect?v=2 request's query string key will be ul. BQ column is device.language will be update to en-ca. The navigator.language won' update.

page_location

By default using the window object's document.location's value, not sure what condition need to update this value.

gtag('set', 'page_location', '/test2');
gtag('event', 'test_gtag_set', { test_id: 'page_location'});

The collect?v=2 request's query string key will be dl. BQ column is event_params.page_location will be update to /test2.

page_referrer

By default using the window object's document.referrer's value, if is direct come to the site, document.referrer should be empty and BQ will have no value.

gtag('set', 'page_referrer', 'https://technoapple.com');
gtag('event', 'test_gtag_set', { test_id: 'page_referrer'});

The collect?v=2 request's query string key will be dr. BQ column is event_params.page_referrer will be update to https://technoapple.com, because of page_referrer has value, event_params will add 2 more values, medium value is referral and source has value is technoapple.com.

page_title

By default using the window object's document.title's value, not sure what condition need to update this value.

gtag('set', 'page_title', 'my title');
gtag('event', 'test_gtag_set', { test_id: 'page_title'});

The collect?v=2 request's query string key will be dt. BQ column is event_params.page_title will be update to my title.

user_id

The user's id provide by the site.

gtag('set', 'user_id', '123');
gtag('event', 'test_gtag_set', { test_id: 'user_id'});

The collect?v=2 request's query string key will be uid. BQ column is user_id will be update to 123. Once this value is set subsequent gtag request will always contains user_id as 123.

user_properties

Additional user preference information, update to 25 additional user properties. name max is 24, value max is 36.

gtag('set', 'user_properties', {
  "data1": "1 data"
});
gtag('event', 'test_gtag_set', { test_id: 'user_properties'});

The collect?v=2 request's query string key will be something start with up, e.g. up.data1. BQ column is user_properties, it should contains the object data1 and value 1 data.

gtag('config', 'G-NFY53GVWDK', {
   'user_properties': {
      "data_10": "10 data"
  }
});
gtag('event', 'test_gtag_set', { test_id: 'user_properties'});