Twilio - Brings voice and messaging to your web and mobile applications.
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
BulkSMS - SMS messaging service provider offering two-way SMS communication services.
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.