DirectChat

DirectChat allows you to create ChatHeads/Chat Bubbles for any application. It manages all your conversation in one place to help you to have a non interrupted conversation. You can also read and reply to all messages privately without ever coming online or showing your last seen. It comes with more than 20 messengers support by default. Additionally, it acts as your own Notification Manager to manage all your notifications in one place. Additionally, You can also customize the chat appearance to suit your needs with different colors and transparency.

Features
ChatHead/Bubble Support for all apps
Recover deleted messages by others in chat.
Privacy Mode - Read messages without coming online or showing last seen!
MultiWindow/MultiTasking - Chat over the top of any window!
DND Mode - Pause the ChatHead Service temporary and stop receiving its notification.
Blacklist Apps
Blocked Users

Premium Features
No Ads
Instant Reply - Quickly reply by tapping on message preview.
Mark messages as read directly from ChatHead
Recent Chats and recall any past conversation anytime
Themes
Unlock all Apps for ChatHeads
Chat Bubble Appearence
Various Predefined Themes
Link Previews

Default Supported Messengers
WhatsApp
WhatsApp Business
Kik
Hangout
Telegram
Allo
Textra
Skype
Facebook Messenger
Threema
Line
Disa
Plus
Slack
GroupMe
Messenger Lite (for Android N+)
Viber
Gmail
Android Messages
Instagram (for Android N+)
Google Voice
YAATA
BBM
Discord (for Android N+)
Wire (for Android N+)

Mark as Read Supported Apps (Pro)
Skype
Telegram
WhatsApp
WhatsApp Business
Allo
Kik
Hangout (Android Auto App required)
Disa
EvolveSms
Threema
Messenger
Textra (Android Auto required & Auto integration in Textra Settings)

Messengers that manually works but are not offically supported yet
Chomp SMS
Hop-eMail
Aqua Mail
EvolveSMS
Pulse SMS
Parallel Space
Most Stock Messaging apps
and many more...

You can add your own by going to app settings and enable the apps for which you want to display chatheads. ChatHeads/Bubbles will appear when it receives its notification.

*Reply functionality will only be visible in apps that support it in their notification.

Disclaimer - DirectChat isn't affiliated with any of the messengers listed above nor does it endorse any of the products. It only lists out compatible messengers and doesn't interact directly with any of them. Instead, it uses Google's public API to read incoming notifications.