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UML diagram tool

UML diagram tool, free and online

Create every common UML diagram - class, sequence, use case, activity, state, component, and deployment - with correct notation. Write Mermaid, drag shapes, or let AI draft it from a description.

Open UML Diagram ToolAll diagram tools
  • AI text-to-diagram
  • 1000+ shapes
  • Real-time collaboration
  • Free to use

Step by step

How to use the uml diagram tool

  1. 1

    Open the UML diagram tool

    Launch Atlas Diagram Studio and pick a UML diagram type - class, sequence, use case, activity, state, or component.

  2. 2

    Model your system

    Add classes with attributes and methods, draw associations, inheritance, aggregation, and composition - or the equivalent for other UML types.

  3. 3

    Generate from text or code

    Describe the model in plain English, paste Mermaid classDiagram syntax, or import code structure to skeleton the diagram.

  4. 4

    Collaborate and export

    Co-edit with your team in real time and export to PNG, SVG, or PDF for the design doc.

Open UML Diagram Tool

Why Atlas Diagram Studio

A diagram tool that is part of your work

Most online diagram tools are throwaway. This one has an AI engine, real-time collaboration, and lives inside the workspace where the rest of your work already is.

  • AI does the first draft

    Describe your UML diagram in plain English - or paste Mermaid - and Atlas generates an editable, validated diagram you can refine, instead of starting from a blank canvas.

  • Real-time collaboration

    Invite your team and build the UML diagram together with live cursors, comments, and version history - nobody emails a screenshot back and forth.

  • Part of your whole workspace

    Unlike a one-off uml diagram tool, this lives inside Atlas - so the diagram attaches to the project, task, or doc it describes and is searchable alongside the rest of your work.

  • AI text-to-diagram
  • Mermaid & .drawio import
  • Real-time multiplayer
  • PNG / SVG / PDF export

More diagram tools

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  • Open the editor

FAQ

Questions, answered.

Is the UML diagram tool free?
Yes. You can create a UML diagram for free in Atlas Diagram Studio. A free Atlas account lets you save, collaborate, and use the rest of the all-in-one workspace.
Can I make a UML diagram with AI?
Yes. Describe what you want in plain English, or paste Mermaid, and the AI engine builds an editable UML diagram - validating the structure and auto-fixing common mistakes before it renders.
Can I export my diagram?
Yes. Export to PNG, SVG, and PDF (plus Mermaid source and .drawio), so your diagram drops cleanly into docs, slides, and code repositories.
Does it work in the browser?
Yes. Atlas Diagram Studio runs in any modern browser with nothing to install, with real-time collaboration built in.

Ready when you are

UML Diagram Tool - and 11 more diagram tools.

Atlas Diagram Studio makes every diagram - flowcharts, UML, ERDs, architecture, mind maps - with AI text-to-diagram and real-time collaboration, inside an all-in-one workspace. Start free.

Get started freeSee pricing
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