https://techcrunch.com/2017/09/18/august-announces-new-smart-locks-and-a-smart-doorbell/

August has updated its smart lock line with a new Pro version with Bluetooth, HomeKit, and Wi-Fi support, as well as the more basic model for $149. They’ve also announced the Doorbell Cam Pro for $199 that lets you see visitors approaching your domicile, even at night.

The August is unique in that it depends entirely on the phone for usage, improving security (or reducing usability) but eschewing the keypad. To install it you mount it on the inside of the deadbolt you already have and the system locks and unlocks your door automatically.