Avg Time on Site: how is the last page visit handled?

[marcochiodo]

Looking at the source, avg_time_on_site is calculated from time_to_next_event, filtered to exclude values greater than 30 minutes or NULL. This means the last event in a session (where time_to_next_event is NULL) is excluded from the average.

The tracker script also doesn't seem to send any outgoing events (sendBeacon, visibilitychange, pagehide, etc.), so we were wondering: is the time spent on the last visited page intentionally not considered in the avg time calculation?

We tested sending a custom event via the API:

POST /api/event
{ "name": "heartbeat", "entity_id": "...", "url": "..." }

This gets recorded and correctly populates time_to_next_event on the previous event. We could use setInterval with the exported event() function as a workaround.

Two questions:

1. Is there a recommended way to capture time on the last page of a session?
2. Do custom event names like "heartbeat" affect the hits count in the dashboard, or are only "pageview" events counted?

Thanks!