Duo lets you make one-on-one video calls with anyone else who has the app; all you need to hit them up is their phone number. At present, it’s fairly basic and its only other notable feature is Knock Knock, which lets you see live video of your caller before you pick up.
Google says it’s built Duo for speed and simplicity; the app adjusts the video resolution depending on the speed of your connection automatically and ensures that all calls are fully encrypted.
With Duo, you get an incredibly simple video calling app that is only for performing 1-on-1 chats with friends, family, and whoever else you have a phone number for. And yes, you do indeed need a phone number in order to use Duo, as that is the means for signing up. Once you have done that, though, video calling someone is as easy as tapping their name in a contact list.
Google uses a protocol called QUIC in Duo that allegedly allows for better video quality than competing video chat services. Duo can detect poor WiFi quality and flip over to mobile data seamlessly as well.
As of right now, Duo is still showing for me as open for registration rather than for installs, so we’ll update this post when it finally goes live.