One of the most common issues with VoIP apps is the audio quality and Viber is one of the few apps that address this issue quite well. Viber uses a HD voice engine to offer even better quality audio.

Viber integrates with your phone’s user interface for data and notifications. It displays your favorites contact with thumbnails on top followed by your phonebook. A useful feature is that it highlights the contacts that already use Viber with a sticker. You can select a contact to view their profile and can place a free call or send a text message.

The call quality is loud and clear and you get minimal lag. Like other calling apps, Viber lets you switch to speakerphone or mute a call. As it supports free messages also, you can select a contact and start chatting with him/her.

Viber lets you send a photo, video, audio messages as well as stickers and emoticons. You can also draw a doodle and send it to a contact over chat. Additionally, Viber supports adding up to 100 people in a single group chat.

As it integrates with the device’s user interface, Viber displays messages in pop-up boxes. You can read incoming message and reply to them from within the pop-up box – no need to launch the app to reply. This is useful as it allows for better multitasking for the user.