It is an application that allows you to view messages on this app without open messenger app so that you can avoid notifying sender which you read a message.
"Message secretly viewer!" can view message when I wonder if they read that the others does not wish to distress Did you? So Message view secretly!" using the View!
Please check detailed usage through the Help feature of the App
Support Kakao Talk, Line, Tick-tock, Viber, Telegram, Facebook, QQ, Wechat, Whatsapp