Twilio - Brings voice and messaging to your web and mobile applications.
Plivo - Plivo simplifies your customer engagement.
TeleSign - TeleSign offers end-to-end communications Platform as a Service.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
MirrorFly - World's Most Scalable Voice, Video & Chat SDK for Small, Medium & Enterprises
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.