
Description: Zulip is an open-source team chat software that focuses on threaded conversations to improve productivity and organization. It has features like public/private streams, emoji reactions, integrations, and customizable notifications.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Tango is a free and open source, cross-platform program for video calling and instant messaging using Voice over IP. It offers encryption, group conversations, file transfers, customizable user profiles, and other features.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API