kitio.aiDiagramming AI vs OnUML
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Diagramming AI starts at See pricing page and OnUML starts at See pricing page. Check both pricing pages for current plans.
At a glance
Best for
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Prompt to diagram
- Five diagram engines
- Live preview
- Chat editing
- Excalidraw themes
- Read-only share links
- Text or image to diagram
- Mermaid and PlantUML editors
- Draw.io canvas mode
- Editable mind maps
- AI code repair
- MCP server
| Feature | Diagramming AI | OnUML |
|---|---|---|
| Best for | Generate and edit Mermaid, PlantUML and Excalidraw diagrams by chat | AI diagram maker for Mermaid, PlantUML, Draw.io and mind maps |
| Category | Design | Design |
| Pricing model | Freemium | Freemium |
| Starting price | See pricing page | See pricing page |
| Free plan | Yes | Yes |
| Made by | Diagramming AI | OnUML |
| Based in | – | – |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Diagramming AI starts at See pricing page and OnUML starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
Prices in USD, checked Oct 29, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Diagramming AI
- Supports five diagram formats
- Output stays editable as code
- Theme changes don't need regeneration
- Pricing is not shown on the homepage
- Share links are read-only
OnUML
- Four diagram formats in one place
- Fixes broken diagram code
- Free daily credits
- Pricing hidden behind sign-in
- Daily free credits are small
- Formal UML still needs some know-how
Which one should you choose?
Choose Diagramming AI if you want:
- Supports five diagram formats
- Output stays editable as code
- Theme changes don't need regeneration
Watch out: pricing is not shown on the homepage.
Choose OnUML if you want:
- Four diagram formats in one place
- Fixes broken diagram code
- Free daily credits
Watch out: pricing hidden behind sign-in.
Diagramming AI vs OnUML FAQ
What is the difference between Diagramming AI and OnUML?
Diagramming AI: Generate and edit Mermaid, PlantUML and Excalidraw diagrams by chat. OnUML: AI diagram maker for Mermaid, PlantUML, Draw.io and mind maps. Both are design tools.
Is Diagramming AI or OnUML cheaper?
Diagramming AI starts at See pricing page and OnUML starts at See pricing page. Check both pricing pages for current plans.
Do Diagramming AI and OnUML have free plans?
Diagramming AI: Yes. OnUML: Yes.
Who makes Diagramming AI?
Diagramming AI is made by Diagramming AI.
Who makes OnUML?
OnUML is made by OnUML.
Which should I choose, Diagramming AI or OnUML?
Choose Diagramming AI if you value supports five diagram formats and output stays editable as code. Choose OnUML if you value four diagram formats in one place and fixes broken diagram code.