kitio.aiAdded Nov 5, 2026
OnUML
FreemiumAI diagram maker for Mermaid, PlantUML, Draw.io and mind maps
What is OnUML?
OnUML generates diagrams from text or images in four modes: Mermaid, PlantUML, Draw.io and mind maps. Developers, analysts and students can then edit the result as code or on a canvas, preview it live and export or share it.
Mermaid suits quick documentation diagrams, PlantUML covers formal UML and technical modeling, Draw.io gives a freeform canvas with drag-and-drop shapes, and the mind map mode lets you add and move nodes directly. Changes from prompts or code render in real time.
When Mermaid or PlantUML code has syntax errors, a one-click AI repair fixes it so the diagram renders again. The site also has an examples library and an MCP server, and registered users can claim free credits each day.
Features
- Text or image to diagram
- Mermaid and PlantUML editors
- Draw.io canvas mode
- Editable mind maps
- AI code repair
- MCP server
Tags
Releases
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Organization
OnUML
Listed by kitio.ai · unverified owner
Pricing
- Pricing model
- Freemium
- Paid options from
- Not listed
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Pros and cons
Pros
- Four diagram formats in one place
- Fixes broken diagram code
- Free daily credits
Cons
- Pricing hidden behind sign-in
- Daily free credits are small
- Formal UML still needs some know-how
Prompts & results
No prompts yet. Add your own prompt and output to help others use this tool.
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Reviews
Q&A
What is OnUML?
OnUML generates diagrams from text or images in four modes: Mermaid, PlantUML, Draw.io and mind maps. Developers, analysts and students can then edit the result as code or on a canvas, preview it live and export or share it.
Can OnUML create a diagram from an image?
Yes. It accepts text and image inputs, so a sketch or screenshot can be turned into an editable diagram.
Does OnUML fix broken PlantUML or Mermaid code?
Yes. Paste the code into the editor and use the one-click AI repair to correct syntax errors.
How much does OnUML cost?
OnUML is freemium.
Is there a free version of OnUML?
Yes. OnUML has a free plan, and paid plans add more usage and features.
What are the main features of OnUML?
Text or image to diagram, Mermaid and PlantUML editors, Draw.io canvas mode, Editable mind maps, AI code repair, MCP server.
Who makes OnUML?
OnUML is made by OnUML.
What are the best alternatives to OnUML?
Popular alternatives include Diagram Generator, ChatFlowchart, Diagramming AI.