What are some alternatives?
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Bandwidth - Track your Wi-Fi hotspot usage. Zero configuration required. It just works.
Plivo - Plivo's Voice API enables businesses to build Voice apps to reach customers globally in 200+ countries. Try Plivo's Voice API for free. Instant Sign Up.
SendBird - SendBird is messaging-as-a-service.
Voxbone - Fully compliant, enterprise-ready voice and SMS on demand. Build local presence on a global scale with elastic SIP trunks and phone numbers. Try for free.
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.