What are some alternatives?
Twilio - Brings voice and messaging to your web and mobile applications.
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.
VoxImplant - Voximplant is a software program that allows businesses to automate communications by setting up automatic communication systems in the cloud.
RingCentral - RingCentral is the leading provider of cloud-based communications and collaboration solutions for small business and enterprise companies
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.
CrazyCall - CrazyCall is cloud based platform for sales and marketing teams doing cold calling, market research, information or loyalty campaigns.