GA4 Breakdown Report

GA4 breakdown report: sessions / users / key events (conversions) / total events by a dimension. dimension: channel (default) | source | medium | source_medium | page | landing_page | country | device | date | event. The channel/source breakdown answers 'which traffic converts'.

dimension='event' splits by EVENT NAME, which is the only way to isolate ONE key event. Without it `conversions` is the SUM of every key event in the property, so a property with purchase + form_sent + mql reports a single number that cannot be reconciled against what an ad platform counted — the most common check in any paid media audit. ga4_list_conversions shows which event names are key events. dimension2 crosses a SECOND dimension with the first (dimension='event' + dimension2='source_medium' gives events per traffic source). Rows then carry both dimension fields. `events` is the raw event count and `conversions` counts only key events, so on an event row the two differ whenever that event is not a key event. Every GA4 row is retained: limit controls only the number returned in this response (0 = as many as fit, about 370 KB); when has_more is true, call again with page_token=next_page_token to retrieve the remaining rows without re-running the report or using another credit.