What are some alternatives?
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.
Twilio - Brings voice and messaging to your web and mobile applications.
SendBird - SendBird is messaging-as-a-service.
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
Applozic - Chat API & In-App Messaging SDK for Mobile & Web Apps Innovate fast, save development cost and delight users with a scalable, secure and customizable Chat
Apache Tika - Apache Tika toolkit detects and extracts metadata and text from different file types.