Rakuten Viber, or simply Viber, is a cross-platform voice over IP (VoIP) and instant messaging (IM) software application owned 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 Rakuten Viber Out. As of 2018, there are over a billion registered users on the network.
The software was started in 2010 by a company that was apparently Cyprus-based in 2024 Viber Media, which was bought by Rakuten in 2014. Since 2017, its corporate name has been Rakuten Viber. It is based in Cyprus with offices in London, Manila, Moscow, Paris, San Francisco, Singapore, Tokyo, and Beijing.