Class Diagram Maker — AI UML Class Diagram Generator

A class diagram shows the blueprint or template for objects in a system—the classes with their attributes, methods, and relationships. An object diagram shows instances of those classes with actual values at a specific point in time. Class diagrams are used for design and code generation, while object diagrams illustrate concrete examples and runtime states. Both follow UML 2.5 standards.

UML class diagrams are essential for object-oriented design. They help you visualize object relationships, plan inheritance hierarchies, define interfaces, and document system architecture before writing code. Class diagrams serve as a bridge between business requirements and implementation, improve team communication, support code generation, and enable better design decisions early in development.

In UML class diagrams, inheritance is shown with a solid line with a hollow triangle (arrowhead) pointing from the child class to the parent class. For example, "Employee" (child) inherits from "Person" (parent). The inheritance arrow indicates an "is-a" relationship. Cloudairy's AI-powered diagrams automatically generate correct inheritance notation following UML 2.5 standards when you describe class hierarchies in plain English.

Aggregation represents a "has-a" relationship where a part can exist independently (hollow diamond at the aggregating class). Composition represents a stronger "part-of" relationship where parts cannot exist without the whole (filled diamond at the containing class). For example, a Department (whole) can contain Employees (parts) in aggregation, but an Employee cannot exist without a Company (composition). Both are properly notated in Cloudairy's class diagrams.

Yes. Cloudairy supports reverse engineering Java, Python, and C++ source code into UML class diagrams. Upload your code files or paste code snippets, and Cloudairy's AI analyzes classes, attributes, methods, and relationships to generate accurate diagrams. This feature is perfect for documenting legacy code, understanding existing architectures, or creating visual documentation from production systems.

Cloudairy exports class diagrams to multiple formats: PNG, SVG, PDF, JPEG for sharing and documentation; Visio (.vsdx) for Microsoft Office workflows; draw.io (.xml) for collaboration and further editing; Mermaid for documentation repositories; PlantUML for CI/CD integration; and PowerPoint for presentations. You can also export code directly in Java, Python, or C++ from your diagrams.

Yes. Cloudairy's real-time collaboration features allow multiple team members to work on the same class diagram simultaneously. See live cursor positions, leave comments on specific elements, mention teammates, track version history, and maintain design consistency across teams. This is ideal for architecture review sessions, design workshops, and distributed teams working across time zones.

Yes. Cloudairy generates production-ready code directly from your UML class diagrams in Java, Python, or C++. Configure class properties, method signatures, access modifiers, and relationships in your diagram, then export complete code with proper structure, inheritance, and associations. Code generation accelerates development, reduces errors, and keeps documentation in sync with implementation.

Yes. Cloudairy's free tier includes unlimited class diagram generation with UML 2.5 notation, AI text-to-diagram conversion, and PDF export. Premium plans unlock advanced features like code generation and import, multi-format export (Visio, Mermaid, PlantUML), unlimited team collaboration, version control, and priority support for enterprises.