SmoochBot - Open source on-boarding bot for conversational apps
The Big Book of Churn - The definitive guide to customer churn reduction
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Customer.io - We make it easy to send emails triggered by user behavior. Build, measure and improve your emails to activate and retain users
Hotline - In-app chat,real-time engagement & self-service for your app
Postmark - Postmark is the easiest and most reliable way to be sure your important transactional emails get to the inbox. Simply & reliably parse recieved email to JSON for your webapp.