Standard FeaturesEach doorbell camera has a Wi Fi connection and a mobile app that let you see the video feed and speak with visitors on your doorstep. Video doorbells also use motion detection to track events, which means they don’t record continuously like a security camera, with the notable exception of the Nest Hello. Most doorbell cameras record subjects in both daytime and nighttime conditions, usually at an HD video resolution of 720p or greater. Smart Lock PairingOne of the most exciting features of video doorbells is that you can pair most of them with a smart lock such as the Kwikset Kevo and August Smart Lock to let guests in when you're unable to come to the door. However, the level of integration between a doorbell and lock really depends on the company. This is something we discovered when we linked the doorbells to smart locks we were also testing. The biggest difference comes from doorbells and locks designed to work together. August and Nest make both smart locks and video doorbells, which let you unlock the door without leaving the app, though August is the only smart doorbell that lets you unlock the door from within the call. However, Ring and SkyBell don't make smart locks, but give you a shortcut to partner apps instead. Other Smart Home DevicesAside from smart locks, you can connect the video doorbell to voice assistants and smart speakers, such as Amazon Alexa and Google Assistant, to get notifications and sometimes speak with people at the door. As part of a security system, the unit can help protect your home by detecting motion outside.