Notifly

Notifly is an app that lets you read and respond to all your notifications from any app or even from the lock screen. The notifications will appear in a bubble that lets you respond quickly. Just click the bubble to start writing.

Notifly's list of compatible programs isn't very long but it does include the most important apps: WhatsApp, Telegram, Line, Hangouts, Skype, Tango, KakoTalk, Twitter, Facebook Messenger, Google Messenger, and Plus Messenger. If you receive a message from any of these apps you can respond instantly.

In the configuration options you can customize the notifications received from each app. The easiest way involves customizing the colors of the notifications, but you can also deactivate Notifly for certain apps.

Notifly is a very interesting app that lets you respond to messages sent via practically every messenger app, straight from your device's lock screen.