1. WhatsApp Messenger：
WhatsApp Messenger，或简称为WhatsApp，是Facebook公司拥有的跨平台消息服务。它允许用户发送文本消息，语音消息，进行语音呼叫，视频呼叫，共享图像，文档，用户位置和其他媒体。
2. Viber：
Rakuten Viber，或简称为Viber，是一种跨平台的基于IP的语音和即时消息传递软件应用程序。它允许用户与任何地方的任何人交换媒体，如图像，视频，免费和安全的呼叫和消息。
WhatsApp Messenger和Viber之间的区别：
| Viber | |
|---|---|
| It is owned by Facebook, Inc. | It is also owned by Japanese multinational company Rakuten. |
| It was launched on 3rd May, 2009. | It was launched on 2nd December, 2019. |
| Whatsapp allows to personalize the appearance of the app like choosing a different theme or colors. | Viber requires a Gmail login to get started. |
| Whatsapp is add free. | Viber is not add free. |
| There is no option such that an image which automatically disappears once the person has seen it. | In Viber you can send an image which can disappear once the person has seen it. |
| In whatsapp there is no facebook sign in option. | In Viber there is a facebook sign in option. |
| In whatsapp you can set notifications to snooze mode if you don’t want to be disturbed during a specific time frame. | In Viber you cannot do so. |
| In whatsapp maximum of 256 persons can be there in a group. | In Viber maximum of 200 persons can be there in a group. |
| Whatsapp messenger has no cloud sync. | Viber has cloud sync. |