
Description: Substack is an email newsletter platform that allows writers and publishers to easily create, design, and distribute email newsletters. It aims to let freelance writers and bloggers build direct relationships with readers.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Papyrus.so is a free online document editor that allows real-time collaboration. It has features similar to Google Docs and Microsoft Word Online, allowing users to create, edit, and share text documents, spreadsheets, presentations, and more from any device.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API