Avochato - Text messaging for your business.
SmoochBot - Open source on-boarding bot for conversational apps
Message Me - Website to create your contact business card
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Slack with your Users - Speak to your app's users entirely within Slack
Hotline - In-app chat,real-time engagement & self-service for your app