Twilio - Brings voice and messaging to your web and mobile applications.
MessageBird - Reach 7 billion phones in seconds via SMS, Chat & Voice. Try it for free and improve your communication.
Textlocal - Textlocal is an app that allows for individual and group texting. It is designed for businesses that have employers and employees who need to communicate with each other, making it easier to announce group meetings and special announcements.
Bandwidth - Bandwidth offers SIP trunking, Emergency communications, and Voice & Messaging APIs.
Infobip - A2P messaging platform for enterprises, resellers & mobile operators with global network coverage.
CONTUS MirrorFly - World's Most Scalable Chat APIs & SDKs for Small, Medium & Enterprises