Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
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
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Zoho Desk - Industry's first context-aware Helpdesk Software
Plivo - Plivo simplifies your customer engagement.
Salesforce Service Cloud - Service Cloud integrates customer service with social networks and provides a self-service customer portal and knowledge base system.