Sipnetic is described as 'free VoIP softphone based on the SIP protocol. Sipnetic supports voice and video calls, instant messages, presence information and end-to-end encryption' and is an app in the Social & Communications category. There are more than 10 alternatives to Sipnetic for a variety of platforms, including Android, iPhone, Mac, Windows and Online / Web-based. The best alternative is Jitsi, which is both free and Open Source. Other great apps like Sipnetic are Linphone (Free, Open Source), MicroSIP (Free, Open Source), Zoiper (Free Personal) and CSipSimple (Free, Open Source).
Astian Spika is an instant messaging service focused on speed, security and productivity. With great differences such as integration with Astian Cloud, support for video calls, calls among other features.
Q-municate is a cross-platform app with a wide range of communication features including free messaging, file transfer, push notifications, audio/video calls. Use instant messaging, voice or video calls features to keep in touch with friends and family. Features: