Developer Design Tools

Interactive workbenches for the thinking that happens before the code—model your domain, pressure-test the shape, and export a spec.

CRC Card Designer

Model a class system from a problem statement

Paste a description, harvest candidate classes and responsibilities, build a deck of CRC cards, and get live feedback on god objects, data bags, orphans, and tight coupling. Export to Markdown, JSON, or a Mermaid diagram.

OOP Design CRC Cards RDD

Open tool →

New to Responsibility-Driven Design? Start with the interactive RDD & CRC Cards tutorial, or grab the one-page PDF cheat sheet.