
Description: MailerQ is an open source message queue for sending large volumes of email efficiently. It can process millions of messages per minute with low latency using concepts like event looping, message storage, and parallel processing.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Exim is an open source mail transfer agent (MTA) developed for use on Unix systems. It is lightweight, flexible, and one of the most popular MTAs for Linux and BSD systems. Exim aims to be secure, scalable, and easy to configure.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API