Free, online, and AI‑assisted.
Create clear UML class diagrams in minutes. Define classes, members, visibilities, stereotypes, and relationships with instant preview.
Why this class diagram tool
UML‑accurate, readable, and fast—powered by AI.
UML‑accurate notation
Generate correct class boxes, member visibility symbols, stereotypes, and relationship arrows that follow UML standards.
Smart auto‑layout
Avoid overlaps and tangled lines. The layout engine spaces classes and routes connectors for instant clarity.
Class & member editor
Quickly add properties and methods with type, visibility, static, and abstract flags—no clunky dialogs.
Rich relationships
Create inheritance, composition, aggregation, association, dependency, realization, and links with labels and cardinalities.
Readable styling
Set chart title and font size, and use consistent shapes for easy scanning and presentation‑ready output.
Zoom and pan
Explore large models smoothly with zoom/pan controls for focused reviews and demos.
Bring your structure
Type Classes
Enter class names, stereotypes, and members directly in the editor.
Paste Outline
Paste a simple text outline of classes and relationships to convert into UML.
Use AI Prompt
Describe your system; AI proposes classes, members, and relationships instantly.
Import Spec (Pro)
Upload a simple spec (Pro) to prefill classes and relationships.
Share and export
Download SVG/PNG
Export crisp diagrams for docs, slides, or repos.
Share Link
Send a view link with your latest changes.
Embed Anywhere
Embed the diagram in your wiki or site.
Version Save
Save and update diagrams without rebuilding (Starter+).
About this tool
This AI‑powered maker builds UML class diagrams fast. It focuses on clear notation, readable layout, and easy editing. Start free, no sign‑up required. When ready, save, share, and embed. Ideal for students, developers, and architects.
- ✓UML‑accurate classes, members, and relationships
- ✓Instant preview with smart auto‑layout
- ✓Titles, font size, and zoom/pan controls
- ✓Export SVG/PNG or share a live link
- ✓Free to start; upgrade when you need more
Quick facts
How it works
From idea to clean UML in a few steps.
Describe or start
Type a prompt like what classes you need, or begin with the preview and build from there.
Animal with +name:String; Duck extends Animal; Fish implements Swimmable; Animal +move():void
Edit classes
Use the class editor to add members, types, visibility, static/abstract, and optional stereotypes.
Vehicle «abstract» with +start():void, -vin:String; Service «interface» +serve():Boolean
Connect relationships
Add inheritance, composition, aggregation, association, dependency, or realization and specify labels/cardinalities.
Order 1..* —contains— LineItem; Payment —depends on— Gateway (0..1)
Tweak and export
Set chart title and font size, enable zoom/pan, then download SVG/PNG or embed a live link.
Title: E‑Commerce Domain Model; Font: 14; Export: SVG
Use cases
Built for teams who design and explain systems.
Model domains and APIs
Sketch entities, services, and boundaries to align teams before coding.
Teach UML concepts
Demonstrate inheritance, composition, and interfaces with clean visuals.
Communicate options
Compare alternative designs and document decisions for stakeholders.
Document services and DTOs
Map service contracts, persistence models, and dependencies clearly.
Why choose AI over manual
Less fiddling, more clarity.
Manual UML tools
- ✗Complex setup and dense menus
- ✗Steep learning curve for basic tasks
- ✗Rigid layouts that need constant tweaking
- ✗Hard to keep models updated
- ✗Export and embed are tedious
- ✗Often costly or locked to devices
AI‑assisted maker
- ✓No setup—start free in browser
- ✓Describe your system to generate UML fast
- ✓Auto‑layout and tidy routing by default
- ✓Edit once; regenerate and keep context
- ✓One‑click export and simple embeds
- ✓Affordable plans that scale with you
Frequently asked questions
Is this a free UML class diagram maker?
Yes. You can create, customize, and export UML class diagrams for free. Upgrade only if you want extras like saving versions, embedding, or file uploads.
How does the AI UML class diagram generator work?
Describe the system you have in mind. The AI proposes classes, members, visibilities, stereotypes, and relationships. You can accept, edit, or regenerate parts while the preview updates instantly.
Can I model inheritance, composition, and aggregation?
Absolutely. Choose the relationship type and add labels and cardinalities like 1, 0..1, or 1..*. The diagram uses correct UML arrows and diamonds.
How do I add methods, properties, and visibility?
Open the class editor, add a member, set its type, mark it as method if needed, and pick visibility (public, private, protected, package). You can also mark members static or abstract.
Does it support stereotypes and interfaces?
Yes. Add stereotypes such as «interface», «abstract», «enumeration», or «service». Interface methods and abstract classes display correctly in the diagram.
Inclusive by design
- ✓Keyboard‑friendly navigation and editing
- ✓Readable defaults with adjustable font size
- ✓Zoom and pan for low‑vision accessibility
- ✓Color choices designed for contrast clarity
- ✓Responsive layout for mobile, tablet, and desktop
Your privacy, respected
- •Your diagrams are private until you share a link
- •We never sell your data or diagram content
- •Export anytime—no lock‑in with PNG/SVG
- •Delete diagrams or your account whenever you choose
- •All traffic is encrypted in transit
Build your UML now
Start free, describe your system, and get a clean class diagram in minutes.