Top 10 Chat, Audio & Video Calling API & SDK Providers for Enterprise Business

Any comparison between ChatCamp and Contus Fly? Perhaps someone managed to use both and can give some feedback. Thanks.

What are the best alternatives of Quickblox for including a real-time chat to buy essays cheap in an Android app

Top 10 Chat, Audio & Video Calling API & SDK Providers for Enterprise Business

We used Contus Fly for Librivox volunteering project last summer.