[GA4] Event naming rules

When choosing a name for a new event, follow these rules:

• Event names are case sensitive. For example, my_event and My_Event are distinct events.
• Event names can include English and non-English words and letters.
• Do not use reserved prefixes and event names.
• Event names must start with a letter. Use only letters, numbers, and underscores. Don't use spaces.

Reserved prefixes and event names

The following list is not exhaustive and may be updated periodically. If you try to use a reserved prefix or name, Analytics will display an error message.

Web

Reserved event names

The following event names are reserved and cannot be used:

Note: When you create or modify events in Google Analytics, you can use any automatically collected event names mentioned in the list below.

• app_remove
• app_store_refund
• app_store_subscription_cancel
• app_store_subscription_renew
• click
• error
• file_download
• first_open
• first_visit
• form_start
• form_submit
• in_app_purchase
• page_view
• scroll
• session_start
• user_engagement
• view_complete
• video_progress
• video_start
• view_search_results

Reserved event parameter names

The following event parameter names are reserved and cannot be used when creating custom dimensions and metrics:

• cid
• currency
• customer_id
• customerid
• dclid
• gclid
• session_id
• sessionid
• sfmc_id
• sid
• srsltid
• uid
• user_id
• userid

Additionally, parameter names cannot begin with:

• _ (underscore)
• firebase_
• ga_
• google_
• gtag.

Reserved user property names

The following user property names are reserved and cannot be used when creating custom dimensions:

• cid
• customer_id
• customerid
• first_open_after_install
• first_open_time
• first_visit_time
• google_allow_ad_personalization_signals
• last_advertising_id_reset
• last_deep_link_referrer
• last_gclid
• lifetime_user_engagement
• non_personalized_ads
• session_id
• session_number
• sessionid
• sfmc_id
• sid
• uid
• user_id
• userid

Additionally, user property names cannot begin with:

• _ (underscore)
• firebase_
• ga_
• google_

Reserved item parameter names

The following item parameter names are reserved and cannot be used when creating custom dimensions:

• affiliation
• cid
• creative_name
• currency
• customer_id
• customerid
• item_brand
• item_category
• item_category2
• item_category3
• item_category4
• item_category5
• item_id
• item_list_id
• item_list_name
• item_name
• item_variant
• promotion_id
• promotion_name
• session_id
• sessionid
• sid
• uid
• user_id
• userid

Mobile (Android and iOS)

Reserved event names

The following event names are reserved and cannot be used:

• ad_activeview
• ad_click
• ad_exposure
• ad_impression
• ad_query
• ad_reward
• adunit_exposure
• app_clear_data
• app_exception
• app_install
• app_remove
• app_store_refund
• app_update
• app_upgrade
• dynamic_link_app_open
• dynamic_link_app_update
• dynamic_link_first_open
• error
• firebase_campaign
• firebase_in_app_message_action
• firebase_in_app_message_dismiss
• firebase_in_app_message_impression
• first_open
• first_visit
• in_app_purchase
• notification_dismiss
• notification_foreground
• notification_open
• notification_receive
• notification_send
• os_update
• screen_view
• session_start
• user_engagement

Reserved event parameter names

The following event parameter names are reserved and cannot be used when creating custom dimensions and metrics:

• cid
• currency
• customer_id
• customerid
• dclid
• gclid
• session_id
• sessionid
• sfmc_id
• sid
• srsltid
• uid
• user_id
• userid

Additionally, parameter names cannot begin with:

• _ (underscore)
• firebase_
• ga_
• google_
• gtag.

Reserved user property names

The following user property names are reserved and cannot be used when creating custom dimensions:

• cid
• customer_id
• customerid
• first_open_after_install
• first_open_time
• first_visit_time
• google_allow_ad_personalization_signals
• last_advertising_id_reset
• last_deep_link_referrer
• last_gclid
• lifetime_user_engagement
• non_personalized_ads
• session_id
• session_number
• sessionid
• sfmc_id
• sid
• uid
• user_id
• userid

Additionally, user property names cannot begin with:

• _ (underscore)
• firebase_
• ga_
• google_

Reserved item parameter names

The following item parameter names are reserved and cannot be used when creating custom dimensions:

• affiliation
• cid
• creative_name
• currency
• customer_id
• customerid
• item_brand
• item_category
• item_category2
• item_category3
• item_category4
• item_category5
• item_id
• item_list_id
• item_list_name
• item_name
• item_variant
• promotion_id
• promotion_name
• session_id
• sessionid
• sid
• uid
• user_id
• userid