Viber is a proprietary cross-platform instant messaging voice-over-Internet Protocol application for smartphones developed by Viber Media. In addition to text messaging, users can exchange images, video and audio media messages. The client software is available for Mac OS, Android, BlackBerry OS, iOS, Series 40, Symbian, Bada, Windows Phone, and Microsoft Windows. A Linux version is in development. Viber works on both 3G/4G and Wi-Fi networks.