Rakuten Viber
Viber is a calling and messaging app that connects people–no matter who they are, or where they’re from. Each month, hundreds of millions of people connect, for free, with their loved ones via messaging, high-quality voice and video calls, and more. All one-on-one Viber calls and personal chats, and all group chats are protected by built-in end-to-end encryption, so you can be sure that your conversations are always secure.