Several separate events, or separate occurrences of the same event, could potentially invoke the same HTTP action.

The One Request Per Event setting controls whether the action bundles the HTTP requests.

If this checkbox is clear, the HTTP request is sent once every minute, no matter how many events triggered the action within that time frame. This is the default.

If this checkbox is checked, the request is sent every time an event triggers it. In this case, if ten events trigger the action, the HTTP request is sent ten times, even if all those events occurred within a single minute.

You might want to send one request per event, checkbox checked, if you are trying to log tickets and your ticketing system API does not support bulk create. However, if it does, you probably want a single bulk request every minute, checkbox clear.