Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.

Sensor Tower - Sensor Tower is a platform for app store optimization and app industry intelligence.

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

App Annie - App Annie is a marketing analytics tool available for apps of all kinds. With App Annie, you can track sales, traffic, and a variety of other factors pertinent to monitoring an app's trajectory.

Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

appfigures - Cross-platform app store analytics for all of your mobile apps.