Can an Alarm.com Flex IO sensor report alarms to a monitoring station when opened?

No. The Alarm.com Flex IO^® sensor is designed for property awareness only and cannot forward signals to a monitoring station.  

To self-monitor the Alarm.com Flex IO^® sensor, set up sensor activity monitoring notifications for sensor openings. For more information about setting up notifications, see Create a notification for an Alarm.com Flex IO^® sensor. 

If the customer also has video cameras, an automation rule can be created to trigger a recording when the Alarm.com Flex IO^® sensor is opened. For more information about setting up video recording rules, see Create a video clip recording rule for an Alarm.com Flex IO^® sensor.