
Description: msmtp is a command line SMTP client that can be used to send emails from the Linux command line or scripts. It is lightweight, easy to configure, and supports SMTP authentication, TLS encryption, several mailbox formats and more.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

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: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API