Viber is a mobile app that allows users to make free phone calls and send free text messages to other users.

This uses Voice over IP technology, sending the calls as ordinary internet traffic rather than as a conventional voice call.

The calls can therefore be sent as data over 3G or wi-fi, meaning that they can be completely free. Viber claims that its calls provide higher sound quality than a normal call.

Viber users can also use the ViberOut function, which allows users to call people who don’t have the app at reduced rates on both mobile and landline.

The app works with Android, iPhone and Windows Phone devices, as well as as a desktop application for Windows and Mac.

Viber is similar to other messaging applications such as WhatsApp or Messenger.

Users pay for credits through a credit or debit card or through the in-app purchase option on their device.