
Description: PlantUML is an open-source tool for creating UML diagrams from plain text. It supports all standard UML diagrams like use case diagrams, class diagrams, sequence diagrams, etc. PlantUML allows users to write simple textual descriptions which are then transformed into UML diagrams.
Type: Open Source Test Automation Framework
Founded: 2011
Primary Use: Mobile app testing automation
Supported Platforms: iOS, Android, Windows

Description: SequenceDiagram.org is a free online tool for creating UML sequence diagrams. It allows users to visually represent the interactions between objects in a system. The tool is easy to use with a simple drag and drop interface.
Type: Cloud-based Test Automation Platform
Founded: 2015
Primary Use: Web, mobile, and API testing
Supported Platforms: Web, iOS, Android, API