Event types

GA4 sorts events into four types. What tells them apart is who sends the event, and who picks its name.

• Automatically collected events are sent by GA4 on its own. Examples: first_visit, session_start, page_view.
• Enhanced measurement events are sent by GA4 too, if enhanced measurement is on in the settings. It's on by default and needs no code. Examples: scroll, click, view_search_results.
• Recommended events have names and parameters defined by Google, but your site sends them with its own code. Event names are case sensitive, so use them exactly as written. Examples: view_item, add_to_cart, purchase.
• Custom events have a name you pick. You send them with your own code or create them in GA4 from events you already collect. Use one only when no other type does the job.

The visit shown here is real, from the Google Merchandise Store on 8 December 2020. GA4 sent eight of its 11 events on its own. The three about promotions came from the store's code, because GA4 can't tell what a promotion is on your pages.

Across the whole store, 70% of events were automatically collected, 12% came from enhanced measurement, 18% were recommended, and none were custom.

The last event comes at 1:07, but the session doesn't end there. GA4 closes it after 30 minutes without events.

To watch events arrive on your own site, turn on debug mode and open DebugView in GA4.

Data: a real visit to the Google Merchandise Store on 8 December 2020, from Google's GA4 sample in BigQuery.