
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: aTalk is an open source, cross-platform alternative to Skype focused on accessibility. It has text-to-speech and speech-to-text features to aid communication for people with disabilities.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API