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

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

Live Chat by Sumo.com - Instantly communicate with customers, prospects & visitors

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

Zendesk for Startups - Everything you need for seamless customer conversations.

HelpScout - Help Scout is a simple, straightforward way to provide excellent support