Viber vs Riot.im : Which is Better?

Viber

Viber Free Messenger and Phone Calls. Developed by Viber Media Inc.

License: Freemium

Apps available for Mac OS X Windows Linux Android iPhone

Riot allows teams to communicate across a wide range of collaboration apps.

License: Open Source

Apps available for Online Android iPhone iPad Self-Hosted

Feature	Viber	Riot.im
Group chat
Multiple languages
Push to talk
Voice Call
Animated stickers
Call Transfer
Desktop Sharing
Hidden chat
Phone calls
Secret chats
Video calling
Voice chat
Built-in File transfer
GitHub integration
Group collaboration
Slack integration
Active Directory integration
Add-ons
Chat Bot
Clean design
Community based
Custom widgets
Decentralized
Direct Messaging
DRM Free
Encrypted chat
End-to-End Encryption
Federated
Federation
Integrated File Sharing
LDAP support
Live Chat
MarkDown support
Matrix.org protocol
Message redaction
Mobile friendly
Moderation tools
Per-room avatars
Privacy focused
Privacy-friendly
Read receipts
Real time collaboration
Security & Privacy
File Sending
Server Moderation
Server side history
Social network
Team Collaboration
Text chat
Typing notifications
User Management
User mentions
Video/Audio Calling
Video chat
Video Conferencing
Web-Based
Web Integaration
Stickers
Lightweight
Cloud sync
Ad-free
Security focused
Share your screen
Multi Channel
Peer-To-Peer
Support for Multiple protocols
Extensible by Plugins/Extensions
Custom Backgrounds
Forums
Gmail integration