Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Releans - Communication platform for Messaging and Chatbots
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Plivo - Plivo simplifies your customer engagement.
BudgetSMS.net - Cheap SMS Gateway with simple HTTP API to send SMS messages worldwide.
Infobip - A2P messaging platform for enterprises, resellers & mobile operators with global network coverage.