What are some alternatives?
Twilio - Brings voice and messaging to your web and mobile applications.
Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
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.
Convoso - Convoso's Cloud Contact Center helps SMBs increase sales, marketing and customer service success.
Bandwidth - Track your Wi-Fi hotspot usage. Zero configuration required. It just works.
FluentStream - FluentStream Technologies is an advanced telecommunications company with a core focus on cloud-based applications.