
Description: Postbox is an email client for Windows and macOS that provides a clean, easy-to-use interface for managing multiple email accounts. It supports POP3, IMAP, Exchange, Gmail, Outlook.com, Yahoo and more.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Microsoft Mail and Calendar is a free email and calendar service developed by Microsoft. It comes included with Windows 10 and integrates well with other Microsoft products and services.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API