HiOperator - HiOperator is a virtual assistant that answers phone calls, chats with customers, provides in-app help, takes orders, and provides support.
HelpStack - Open Source mobile help framework to support iOS and Android app users.
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
Chat Center - Chat with one click, no matter what messaging app you use
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Helpshift - Helpshift is an in-game customer support platform that enables mobile apps to improve customer experience, drive higher ratings and increase retention.