watup

Watup is an open source instant messaging app which you can use to communicate with your contacts through this popular messaging service. Send text messages, voice messages, photos, videos, and stickers.

The interface of Watup is a light color scheme with a pixelated wave used as the chat wallpaper. Watup has very strong security features: start private chats with other users and your conversations will be fully encrypted and neither registered the app has an autodestruct option, enable it and your messages will be automatically deleted after a certain amount of time.