Add voice calling to your mobile app

[Connect-EZ]

We are in the midst of developing some APIs and integrating with an SDK that would enable app users to make voice calls directly to each other (from within your app) or the call centre using their data connection.

Has anyone done this? Would it help your business? Would some devs/your business like to participate to test this?

To clarify, we have a working standalone app with all above features. Need help/feedback from someone who might have a working app and wants to add calling functionality within their app.