Viber is a cross-platform instant messaging and Voice over IP (VoIP) app that was first developed and popularised by the Israeli company Viber Media. In addition to instant messaging, users can exchange images, video and audio media messages. The client software is available for Apple iOS, Android, Windows Phone, BlackBerry OS, Nokia Series 40, Symbian, Bada, macOS, and Microsoft Windows. A 64-bit Linux version is available in both .deb (Debian and Ubuntu) and .rpm (Fedora and openSUSE) package formats. It first requires installation on a phone in order to work on a desktop operating system environment. As of February 2014, Viber had over 100 million monthly active users and 280 million registered users.
Viber Media is based in Tel Aviv, Israel, with offices in Belarus and Cyprus, founded by former chief information officer in the Israeli army, Talmon Marco, along with Igor Magazinnik, Sani Maroli and Ofer Smocha, with Marco as its CEO. Viber was initially launched for iPhone on December 2, 2010, in direct competition with Skype. A pre-release version for Android restricted to 50,000 users appeared in May 2011; an unrestricted version was released on July 19, 2012. Viber for BlackBerry and Windows Phone devices was launched on May 8, 2012. On reaching 90 million users on July 24, 2012, group messaging service and HD Voice engine were added to both Android and iPhone applications. Applications for Nokia's Series 40, Symbian and Samsung's Bada platform were additionally announced on the same day.
Initially, the voice calling feature was only available for iPhone and Android applications, with a promise that voice would be added in upcoming versions for Bada, Symbian and Windows Phone applications, with no mention of either Series 40 or BlackBerry OS. The limitation seems to lie in the core of Blackberry OS and Series 40 which doesn't have easy support for VoIP apps.
On September 22, 2012, HD quality phone calls and hold group-messaging sessions were made available for Windows Phone but only for Nokia users, as part of exclusive partnership with Nokia. Viber with voice was officially released for all Windows Phone 8 devices on April 2, 2013.
On July 24, 2013, Viber's support system was defaced by the Syrian Electronic Army. According to Viber, no sensitive user information was accessed.
On February 13, 2014, Rakuten announced they had acquired Viber for $900 million. The sale of Viber earned the Shabtai family (Benny, his brother Gilad, and Gilad's son Ofer) a few $500 million from their 55.2% stake in the company.
On November 4, 2014, Viber scored 1 out of 7 points on the Electronic Frontier Foundation's "Secure Messaging Scorecard". Viber received a point for encryption throughout transit but lost points because communications weren't encrypted with keys that the provider didn't have access to (i.e. the communications weren't end-to-end encrypted), users couldn't verify contacts' identities, past messages weren't secure if the encryption keys were stolen (i.e. the service didn't provide forward secrecy), the code wasn't open to independent review (i.e. the code wasn't open-source), the security design wasn't properly documented, and there hadn't been a recent independent security audit. On November 14, 2014, the EFF changed Viber's score to 2 out of 7 after it had received an external security audit from Ernst & Young's Advanced Security Centre.
On April 19, 2016, Viber Media added end-to-end encryption to their service, but only for one-to-one and group conversations in which all participants are using the latest Viber version for Android, iOS, Desktop or Windows 10. The company said that the encryption protocol had only been audited internally, and promised to commission external audits "in the coming weeks". In May 2016, Viber published an overview of their encryption protocol, saying that it is a custom implementation that "uses the same concepts" as the Signal Protocol.
The actual functionality varies from platform to platform with iOS and Android being the first to receive new features. Viber includes text, picture and video messaging across all platforms, with voice calling available only to iPhone, Android and Microsoft's Windows Phone although HD voice is planned for Windows Phone 8. The application's user interface includes tab bar on the bottom giving access to messages, recent calls, contact, the keypad and a button for accessing more options. Upon installation, it creates a user account using one's phone number as username. Viber synchronises with the phone's address book, so users don't need to add contacts in a separate book. Since all users are registered with their phone number, the software returns all Viber users among one's contacts. In 2012, Viber added smileys and additional graphical messaging images.
Viber is additionally now available on Windows and macOS.
As of December 2013, Viber officially launched Viber Out, a feature that provides users the option to call mobile and landline numbers; thus Viber users can call people not using a Viber app. Viber Out was originally released in November only to help Typhoon Haiyan victims in the Philippines connect with their loved ones. To use the new feature, users have to visit the "More" tab and choose Viber Out. No update is needed for the feature. Viber Out calls to landlines and non-Viber mobile phones around the world are charged at varying rates per minute, requiring users to buy credit.
Viber's desktop version uses TCP and UDP ports 5242, 4244, 5243, 9785, and the standard HTTP/HTTPS ports 80 and 443.
Viber Media is a Las Vegas and Cyprus-registered company with its development centres in Belarus and Israel. The company was founded by Marco and Magazinnik, who're friends from the Israel Defense Forces. The company is run from Israel, with much of its development outsourced to Belarus in order to lower labor-costs. An interesting fact is that back in 2004, before the Viber.com website domain was acquired by founders, it was a home for an adult only website.
Founded in 2010, Viber was co-owned by its four Israeli and Belarusian founders: Marco, Magazinnik, Maroli and Smocha, prior to the startup's $900 million sale to Rakuten. At that sale price, the founders each realised over 30 times return on their investments.
In its first two years of availability, Viber didn't generate revenues. It began doing so in 2013, via user payments for Viber Out voice calling and the Viber graphical messaging "sticker store". The company was originally funded by individual investors, described by Marco as "friends and family". They invested $20 million in the company, which had 120 employees as of May 2013.