
Description: Gmail Peeper is a Gmail add-on that allows users to see who opened their emails and what actions they took. It tracks opens, clicks, replies, and more to give visibility into how recipients engage with emails.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: nPOPuk is an open-source desktop email client for Windows. It supports POP3 and IMAP accounts, has basic email features like contacts, calendar, and tasks, and emphasizes privacy and security.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API