
Description: App Sketcher is a web-based tool that allows users to easily design mobile app prototypes and wireframes. It has a simple drag-and-drop interface to add UI elements like buttons, menus, and input fields. Key features include export options to PNG, PDF, HTML, and code, as well as collaboration tools to share and get feedback on designs.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: Principle is an open-source visual tool for building interactive UIs. It allows designers and developers to design, prototype, animate and develop user interfaces without writing code. Principle focuses on animations and interactions.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API