Google today launched Google Duo, a one-to-one video calling app for Android and iOS. You can download Duo from Google Play and Apple’s App Store, though you may have to wait a bit as this is a gradual rollout — “it will be live worldwide in the next few days.”

Duo is mobile-only, was built to be very fast, thanks to Web Real-Time Communication (WebRTC), and “takes the complexity out of video calling,” according to principal software engineer Justin Uberti. Duo promises fewer dropped calls, and even supports handing calls off between Wi-Fi and cellular connections.

To get started with Duo, all you need is a phone number. You don’t need to create a separate account, nor do you need a Google account. And no, Duo doesn’t use your Google account in any way, according to Google.