reftype 2 means Event
The refresh follows a change in the content, such as a live score update, with no user action.
When to send it
Send 2 when the page or app refreshes the slot because its content changed: a score updates during a game, a live blog posts a new entry, a stock ticker moves. Set it in RefSettings.reftype and add RefSettings.minint if the slot holds each creative for a minimum time.
Buyers know the user may still be watching an event-driven page, but cannot be sure, so many price it between user-triggered and timed refresh. It is confused with 3 (Time) when the event is in fact a periodic poll, and with 1 (User Action) when the user caused the content change. Choose by what triggers the ad request, not by what the page shows.
Example
{
"imp": [
{
"refresh": {
"refsettings": {
"reftype": 2
}
}
}
]
}Fields that carry it
Other values in auto refresh triggers
The auto refresh triggers list page explains the whole list and its common mistakes.