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

Helpshift - Helpshift is an in-game customer support platform that enables mobile apps to improve customer experience, drive higher ratings and increase retention.

Kayako - Help Desk Software and Customer Service Software by Kayako. Improve customer satisfaction, increase sales.

KeyReply - Omnichannel keyboard for mobile teams to respond better and faster.

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

Chat Center - Chat with one click, no matter what messaging app you use