
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: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: KumoMTA is an open source mail transfer agent designed to be lightweight, fast, and secure. It aims to provide a simple SMTP server for receiving, routing, and delivering email without unnecessary complexity.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API