The Sinch SDK for iOS lets developers add voice calling and instant messaging capabilities to their iOS based mobile apps. The SDK handles signaling and audio management. In addition it offers support for:
App to app calling
App to phone calling
Instant messaging to single and multiple recipient
Originally incubated within mobile VoIP giant Rebtel as a developer API, Sinch today announced the launch of its communications platform enabling iOS and Android developers to add a layer of voice and messaging to their apps.