Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
WATI - No-code chatbot builder for WhatsApp Business
Plivo - Plivo simplifies your customer engagement.
edna.io - Start communicating with customers on WhatsApp Business, Apple Business Chat, Viber for Business, Web & Mobile App Chat
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.