The Sifely Door Sensor keeps your door locked and secured!
Check on the Sifely app whether or not your door is open.
Have auto-lock activate when the door is closed. 
Review records of when the door was opened or closed. 
Set alerts to know when the door has been open for a while. 

For full functionally, it is recommended that a Sifely Gateway is installed near the lock to receive alerts outside of bluetooth range.