When comparing Tox vs Viber, the Slant community recommends Tox for most people. In the question“What are the best Skype alternatives?” Tox is ranked 4th while Viber is ranked 8th. The most important reason people chose Tox is:
The code is licensed under GPL (may change in the future) and is available on [GitHub](https://github.com/irungentoo/toxcore).
Ranked in these QuestionsQuestion Ranking
Pro Free and open source
The code is licensed under GPL (may change in the future) and is available on GitHub.
Pro Multiple front-ends for multiple platforms available
At the moment there is no official Tox client, but a selection of 32 and 64 clients for Windows, OS X, Linux and Android is available.
Pro Privacy focused
Tox uses military grade encryption and works completely peer-to-peer.
Pro No need to create an account or add contacts
One of the best things about Viber is how it handles setup and sending messages. Viber uses your existing number as your ID, so you don't need to create a separate Viber account.
Pro Desktop apps allow texting, calling and enables transferring calls between devices
Viber has native apps for both Windows and Mac that allow you to send and receive messages from your desktop. You can also use the desktop to make and receive calls. Synchronizes between all devices you are using Viber on. Allows transferring calls between devices.
Pro Completely free and ad-less
Viber uses data connection and the app is free. There are also no advertisements.
Pro Supports voice calls
Viber has really well implemented voice tech. It has comparable quality to Skype and you can even tranfer calls from your phone to your desktop seamlessly.
Pro Supports 200 person group chat
Viber allows creating groups of up to 200 people on the Android version of Viber. It also has a cool "smart notifications" feature to prevent being overwhelmed with notifications if a lot of people are active in a chat group.
Pro Android Wear support
Viber includes Android Wear support on Android 4.3 or higher and Viber 5.3 or higher.
Pro Combines cellular and data messaging
This has an advantage in that if you text someone who uses Viber it will be free, if not it will just revert to SMS. This means you can replace your standard messaging app with Viber as well.
Pro Clean interface
The interface is simple, functional and intuitive.
Pro See who of your contacts is using Viber quickly
Viber is tied to your phone number so it can quickly see who else in your contacts list is using the application.
Pro Insight and well documented encryption
Viber has made a documentation available, explaining in great details their encryption system and giving good insight on how it works.
Pro Same protocol as used in Signal
Viber's protocol uses the same concepts of the "double ratchet" protocol used in Open Whisper Systems Signal application.
Pro Public chats
It's possible to be a fly on the wall on other group or one-to-one chats that have been opened up to the public. These public chats are often promotional chats with celebrities.
Pro Keys only on device
Starting with Viber 6.0 the encryption keys are stored only on the clients themselves, not even Viber itself has access to them.
Con Early stages of development
Since Tox is relatively new, it has important features missing (like group video) and requires a proper code review before it can be deemed reliable and ready for everyday use.
Con The company evades U. S. tax
The company uses the common practice of tax haven addresses in order to avoid paying US taxes despite being registered in Delaware.
Con No web client
You cannot login from the web to send and receive messages.
Con Constantly on
Need apps like Greenify to stop it from being constantly on and active, even if you don't use it.
Con Constant reminders of messages
If you don't check your messages (say your in a group chat and simply don't check all of them), it will flood your notifications.