
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: Postfix is a popular open source Mail Transfer Agent (MTA) that routes and delivers email. It is a fast, easy to administer, and secure alternative to Sendmail. Postfix handles basic email routing and delivery well.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API