Viber allows you to make free calls and send free text messages from your Android device to anyone who has the app installed.

What can you do with Viber?

Viber works in a similar way to Skype, using VOIP to let you talk for free to other Viber users over 3G or WiFi. It also supports free text messaging, allowing you to send and receive short messages from your Viber friends.

There are plenty of features within the chat interface of Viber that help to liven up your conversations. You can send photos and videos, share your location, add emoticons, and choose from a range of fun stickers to insert into the conversation.

You can customize the background of the messaging screen, choosing a photo from your collection or taking a new one. This background isn't shared with the person you're talking to, however.

How to use Viber

Unlike Skype, you don't need to sign up to Viber to use it. You just register your phone number once, and you'll receive an SMS message with a code. Enter this code into Viber and that's it. You'll never need to sign in again.

All of your phone contacts are automatically imported into the app, and a Viber logo is displayed next to any contact who also has it installed. You can then just click on their name to call them for free - regardless of where in the world they are, or even what phone they are using. If a contact does not have Viber installed, you can still ring them through the app, although you will get charged at the cost of a regular call.

The Viber interface is very clearly laid, making it very obvious how to use the app. The program could do with some more features, though, such as conference calling and video calling.

Viber features push notifications to ensure that you don't miss messages or activity.

How does Viber perform?

The quality of calls with Viber is generally very good, and rivals Skype in this respect - although of course, quality isn't usually as crisp as a cellular call. One downside of Viber is that it doesn't give you the option to make video calls like you can with Skype.

We noticed some issues when cropping chat background images using the iOS version, which threw up some errors, but aside from this, Viber appears to be stable and reliable.

What's new in Viber 3.0?

Viber 3.0 features a redesigned user interface which looks great and really makes the app feel like an embedded part of the OS. There are also some new stickers (though the range is still pretty limited), and Viber 3.0 adds the ability to send video messages.

Another boon of the new version is its support for syncing with the desktop versions of Viber for Windows and Mac. Messages and chat history are now totally synced, and you can even transfer live calls from your phone to the desktop app.

The verdict

Aside from the fact that you can't make video calls with Viber, it's just about the perfect chat app for your mobile. It looks fantastic, makes it easy to chat with friends for free and is a lot of fun to use!