What Makes the Google Duo Video Calling App Different

The video chat mobile app is available on both iOS and Android

iPhone showing Google Duo on its screen in the center of a white desktop, surrounded by a candle, succulent plants, and notebooks

Benjaminrobyn Jespersen / Unsplash

Google Duo — a video-focused chat service — serves as a stand-alone app that's part of Google's broader current offering of consumer-facing communications tools. It serves as one of two complementary apps intended for broad consumer use.

Core Features

Google Duo offers one-to-one video messaging, similar to Apple's FaceTime product.

Available for both Android and iOS, Duo aims to simplify the video chat experience by offering simple controls and only person-to-person communication. It doesn't require a separate account; log in with your phone number, and connect with other Duo users based on their phone number in your contacts list. Duo also offers a web version; Google's use of the WebRTC standard means that desktop clients (even ones not developed by Google) could also work with the service.

Duo offers a unique feature called Knock Knock that plays the video stream of a caller so you know who's there and what that person might want before you choose to answer the video call.

Duo calls stream at 720p high-definition video quality, compressed for low-bandwidth phones using a mix of open-source and proprietary standards, including WebRTC. Like Netflix, when Duo senses bandwidth problems, it degrades the quality of the video stream to preserve the state of the connection. Duo will even switch between your cell signal and Wi-Fi to maximize the strength and bandwidth of the call. Duo also features, by default, end-to-end encryption.

Duo App Development

Google continues to iterate the Duo product. In March 2018, the app gained a feature to leave 30-second video messages for call recipients who aren't available to answer, as well as a rudimentary screen-sharing feature.

In October 2017, Duo hooked into the Android Messages, phone dialer, and contacts apps on Google-branded phones; similar hooks into devices offered by other manufacturers follow based on those manufacturers' update plans.

The Google Communications Ecosystem

For years, Google has offered a shifting and sometimes confusing mix of telecommunications products for home consumers:

  • Google Talk/Google Chat — a primarily text-based messaging tool, eventually supporting some video capability, that was discontinued in 2015
  • Google+ Messenger — a chat tool for Google+ users, eventually merged into Hangouts
  • Google Hangouts — originally a video service for Google+, then the default unified chat/video app for all Google customers, now focused on enterprise customers with a split between Hangouts Meet (video) and Hangouts Chat (text)
  • Google Voice — a consumer VoIP platform, similar to Skype, which launched as a stand-alone app and now sees its core technology merged into Hangouts
  • Google Duo — person-to-person simple video calling
  • Google Allo — individual and group text messaging, discontinued as of March 2019

Google's strategy has shifted as its service portfolio has changed and as the strategy of Alphabet, its parent company, has evolved. In addition, Google's commitment to open standards waxes and wanes in light of competitive pressures. Duo, for example, supports WebRTC but Hangouts uses proprietary algorithms imperfectly interoperable with web standards.


Google Duo is a solid and easy-to-use mobile app for person-to-person video chat, with a few nifty features layered on top. If you and your friends and family are wedded to the Google communications ecosystem, you'll find Duo to be fast, convenient, secure, and simple.

The challenge, however, is that Google's been notorious for building and discarding different messaging apps every few years; the company's strategy doesn't appear to be especially user-friendly and the odds that Duo will hang around for the long run are anyone's guess.

The problem, in a nutshell, isn't with the app — which is solid and improving — but with the ecosystem. When the market is saturated with video-chat apps, the friction to get a reasonably large number of users to use an app increases. Because Duo replicates most of the functionality of Hangouts, but it also competes with Facebook Messenger, Skype, Viber, WhatsApp, and a host of almost identical but more widely established competitors, the odds that people will flock to Duo decline, especially when the logic behind using more than one video-chat app service at the same time just isn't sound. Without a critical mass of users, the app platform will fail, no matter how good it might be in theory.

So, give Duo a try — it's a solid app. Assuming, of course, any of your contacts can be persuaded to use it.