
Description: RebTel is an open-source alternative to Skype focused on privacy and security. It offers encrypted messaging, audio/video calls, screen sharing, and other communication tools.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: FooCall is a free and open source voice over IP software for making audio or video calls over the internet. It allows users to make high quality calls for free to other FooCall users.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API