
Description: NikaMail is an open-source, privacy-focused email service. It allows users to send and receive encrypted emails for free without ads or user tracking. NikaMail uses end-to-end encryption to keep emails private.
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