Boss Key

Boss Key is a development tool for creating and testing card games. Its visual modules take you through card design, data configuration and gameplay testing without requiring programming. Built-in templates and real-time previews help you turn ideas into playable trading card games.

Design and test games

In the Card Editor, you define cards’ attributes, skills, art and sound effects. The Data Manager lets you configure structured content such as modes, classes and levels. You can also define skill logic and new rules, customize existing systems or build them from scratch.

The software constructs game logic from your configuration data, so you can playtest and validate your designs inside the tool. You can extend both the game and the editor with code, adding custom logic and feature modules for more complex gameplay and systems. AI-assisted tools can help with repetitive configuration, content generation and editing tasks.

Share and play

Boss Key integrates with the Steam Workshop, where you can publish creations, gather player feedback and refine your content. You can also set up rooms to play custom card or board games with friends, collaborate remotely or demonstrate game ideas.

More for development

Source code licensing and technical support are available. The tool is intended for players who make and share custom cards, as well as indie developers, designers and small development teams.