Chat Center - Chat with one click, no matter what messaging app you use
HelpStack - Open Source mobile help framework to support iOS and Android app users.
Hotline - In-app chat,real-time engagement & self-service for your app
Helpshift - Helpshift is an in-game customer support platform that enables mobile apps to improve customer experience, drive higher ratings and increase retention.
LiveMessage from Salesforce - Make mobile messaging a cornerstone of customer service
Outbound Apps by Intercom - Embed apps right inside your messages