Events
GA4 Events vs Key Events
Updated 2026-09-043 min read
Short answer
Every interaction GA4 records is an event. A key event is an ordinary event you have marked as important, so Analytics reports it as a measure of success. The marking changes reporting, not collection.
GA4 has one unit of measurement: the event. A screen view is an event, a purchase is an event, a button tap you named yourself is an event. What separates the trivial from the meaningful is not the data — it is a label you apply.
Three kinds of event
| Kind | Where it comes from |
|---|---|
| Automatically collected | The SDK sends it without you writing code |
| Recommended | Standard names Google defines for common actions |
| Custom | Names you invent for what matters in your app |
Recommended events are worth using where one fits. Using a standard name means Analytics can interpret the event and populate reports built around it; inventing your own name for the same action gets you a number with no context attached.
What a key event is
A key event is an ordinary event you have marked as representing success. It is a declaration about meaning, made in the Analytics interface rather than in your app. The event was already being collected; marking it changes how prominently it is reported and makes it usable in the places Analytics reserves for outcomes.
Note: Marking is not retroactive in the way people hope. It changes reporting going forward rather than reclassifying your entire history, so plan for the mark and the comparison period to line up.
Choosing what to mark
The useful test is whether you would change your product plans if this number moved. A screen view rarely passes it. Completing a workout, finishing onboarding, or making a purchase usually does.
- Mark the moment a user gets the value they came for, not the step before it
- Keep the list short — if everything is a key event, the label stops meaning anything
- Prefer one event that clearly represents success over several that partially do
screen_view → ordinary event, high volume, low meaning workout_start → ordinary event, useful for funnels workout_complete → key event: this is the point of the app subscription_start → key event: this is the point of the business
Naming, and why it bites later
Event names are matched exactly. A typo does not raise an error; it creates a second, quietly separate event that splits your data in two. This is the failure mode that costs the most time, because everything looks fine until you notice a number is half what it should be.
Careful: Check new event names in DebugView the first time they ship. It takes a minute and catches the mistake while it has affected one day of data instead of three months.
How this looks in Appnaly
Appnaly shows your most frequent events and screens per app, which is often the fastest way to notice that something is named wrong — a misspelled variant tends to appear in the list right next to the correct one. It reads whatever names GA4 holds and does not rename or merge them, because guessing that two similar names mean the same thing would be exactly the wrong kind of helpfulness.
For following a sequence of events to an outcome rather than counting them individually, funnels are the right shape, and they have their own article.