I use Viber a lot on my Android phone, but recently I am having some problems with it. Some calls never happen, some messages take a lot of time to be delivered and I have also noticed some network connection instability. Are there any other free apps out there that are similar to Viber? Have you tried any, and what's your opinion about them?
If you don't like Skype you can try Tango. Tango is a cross platform application for free video and voice calls. It is available on Android and iOS devices, but also available on desktop PC and Windows 7 Phones. Log In
I don't use Viber. But there are many apps like these that allow you to make calls and text using a WiFi connection. Here are some great apps that could be used as an alternative to Viber: -Line -WeChat -WhatsApp Messenger -KakaoTalk -Facebook Messenger -Cubie -Yahoo Messenger You don't need all these apps though. Just choose one and stick with it.
I take for granted that you already know the most popular apps and for that reason I'm going to recommend some free alternatives. Yuilop is an instant messaging application that allows to send messages and make calls to any unlimited cell without spending a dime. It thus resembles the popular WhatsApp or Skype. On the other hand, you can try Fring, an application that besides making free calls worldwide using Internet also offers the ability to make video calls and group video chat with up to four people. Finally, there is the option of Nimbuzz, an application similar to the other apps. Surely you will find the perfect application for your requirements. Good luck with that.
Skype, wechat and tango are the similar android application similar to viber. To get a more application search on a google for that.