Twilio - Brings voice and messaging to your web and mobile applications.
WikiPro - All-in-one Business to Customer Communication
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
Heymarket - The professional way to text message. Your customers are mobile. Heymarket helps you manage those relationships from your smartphone.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Respond Flow - The Mailchimp of SMS