Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
SmoochBot - Open source on-boarding bot for conversational apps
ChatWoot - Open-source omnichannel customer engagement platform
tawk.to - tawk.to is a free live chat app that lets you monitor and chat with visitors on your website or from a free customizable page
Hotline - In-app chat,real-time engagement & self-service for your app
MomentCRM - MomentCRM is a platform for support, sales, marketing, and product development.