
Description: OpenSMTPD is an open source SMTP server daemon for Linux and BSD operating systems. It aims to be a free, secure, and featureful SMTP server for both hosting providers and end users.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Haraka is an open source SMTP server written in Node.js. It is designed to be easy to install and configure, while also offering excellent performance and reliability. Haraka aims to provide a secure, flexible, and scalable SMTP solution.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API