Viber

Rakuten Viber, or simply Viber, is a cross-platform voice over IP and instant messaging software application operated by Japanese multinational company Rakuten, provided as freeware for the Android, iOS, Microsoft Windows, macOS and Linux platforms. Users are registered and identified through a cellular telephone number, although the service is accessible on desktop platforms without needing mobile connectivity. In addition to instant messaging it allows users to exchange media such as images and video records, and also provides a paid international landline and mobile calling service called Viber Out. As of 2018, there are over a billion registered users on the network.