The Truth About GA4 Key Event Name Length Limit

Author

Himanshu Sharma
November 23, 2024

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💀 ☠ The Google documentation on the length of event name in GA4 is a bit misleading.

The documentation seems to suggest that "_c" is appended to the length of the event name to mark the event as a key event. 👇

So, one might conclude that the length of an event name should not exceed 38 characters, leaving room for the "_c" suffix.

In GA4, when an event is marked as a key event, the "_c" is not actually appended to the event name itself. Instead, it is added as a parameter ("_c=1") to the network request.

If an event name exceeds 40 characters, only the first 40 characters are used in the matching condition for the conversion events list.

This matching is done client-side in the browser or app.

This clarification is important because it means users can utilize the full 40 characters limit for event names without worrying about leaving space for a "_c" suffix.

The documentation should be updated for accuracy to reflect that "_c" is appended to the network request instead of the event name.

If an event name exceeds 40 characters in GA4, it will still be recorded as an event with the event name truncated to the first 40 characters. But it won't be recorded as a key event.