We are using Opsgenie to handle all our alerts. There is no native integration, so we use actions based on webhooks. We run a Lambda every hour to set the correct action to each monitor.

The problem here is that there is always a period of maximum one hour, where no action is attached to a newly created monitor, so no alerts will be sent during that period.

A simple solution would be to allow a default action to be configured in the DEFAULT Notification Profile. That way an action is always attached and we will always be notified.