Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Synthesio - Synthesio is a social intelligence tool or a marketing software that is specially made for the purpose of social media monitoring and social analytics.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Swift Social - All-in-One Social Media Growth and Management Tool
Plivo - Plivo simplifies your customer engagement.
Opteo - Opteo searches for statistically significant patterns in an account and creates "optimization tasks" to improve account performance.