Structural UML
Class Diagram Maker
Build a UML class diagram in your browser. Start from the template, rename types to match your domain, and export when the structure is clear.
Features
- Live editor for class diagram maker
- Starter template included on the page
- PNG and SVG export
- No install required
Need a blank canvas? Open the full UML studio.
What you can model
Class diagrams show types, fields, operations, and relationships such as association, inheritance, aggregation, and composition. Use them for domain models, API resource shapes, and design reviews before a large refactor.
How to use this maker
Edit the PlantUML in the editor. Add a class block for each type, list attributes and methods, then connect relationships. The preview updates as you type. Download PNG or SVG for docs and pull requests.
Notation that matters
Visibility is often written as + public, - private, and # protected. Inheritance uses a hollow triangle toward the parent. Composition uses a filled diamond on the whole. Multiplicity labels such as 1, *, or 0..1 sit on association ends.
Keep the diagram readable
Limit one diagram to a single bounded context. Hide trivial getters on overview diagrams. Prefer names from the product language over abbreviations.
Frequently asked questions
Is this class diagram maker free?
Yes. You can create and export diagrams in the browser without a paid plan.
Can I work entirely online?
Yes. This page is a browser editor with live preview. No desktop install is required for everyday drafting.
How is this different from a Java or Python class diagram page?
This page is the general class diagram tool. The Java and Python pages use starters and wording tuned to those languages.
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Browse the full UML diagram tools directory or return to the UML diagram hub.