Viber

Viber is a free and cross-platform software project that allows you to make free calls or send free text messages to your family members, friends and colleagues who use Viber on a supported operating system. It is also possible to make calls or send SMS messages to any mobile network or device, in any country.

It offers high-quality HD voice calls

Key features include high-quality HD voice calls, the ability to syncs contacts, call history and messages with a mobile device, as well as to create complete syncs between a Linux PC and a mobile device.

It was never easier to make free calls

The application also supports transfers for ongoing calls between a mobile device and your Linux box, group conversations, image, sticker and text messages, and the ability to call any Viber without paying a dime.

Requires no registration, invitation or passwords

Viber is extremely easy to use, no registration, invitation or passwords is required to make free calls to other Viber users. You just download and install the application on your Linux box (see below for supported distributions) in order to make free voice calls or send text messages.

It has only been tested with Ubuntu

Officially, the application has only been tested with Ubuntu, world’s most popular free operating system, supporting both 32-bit and 64-bit hardware platforms. Being distributed as a DEB file, Viber can be easily installed on other Ubuntu-based OSes, as well as Debian-based distributions. It can also be easily installed on other Linux distros from their default software repositories (e.g. Arch Linux).

It’s a multi-platform application

The best feature of Viber is that it actually works as advertised! It’s a multi-platform application that works well on GNU/Linux, Microsoft Windows and Mac OS X operating systems. Mobile OSes like Windows Phone, iOS, Android and BlackBerry are also supported by Viber.