OnUml
AI-Powered Mermaid UML Generator
Free269 impressions#740 of its week
OnUML is a browser-based AI-powered tool that generates and edits Mermaid, PlantUML, Draw.io, and mind-map diagrams from natural language or images.
- for
- Developers, technical writers, and software architects who need quick diagram creation.
- pricing
- freemium
Key features
- AI-Powered Diagram Generation — Create Mermaid, PlantUML, Draw.io, or mind-map diagrams from natural-language or image prompts.
- Live Real-Time Preview — See diagram changes instantly as you edit code or drag-and-drop elements.
- One-Click Code Repair — Automatically detect and fix syntax errors in PlantUML or Mermaid code.
- Project-Based Organization — Save diagrams by project and manage multiple workspaces.
- Version History — Access and restore previous diagram versions to avoid accidental loss.
- Export & Share — Export diagrams as PNG or SVG and share via link.
- Multi-Mode Workspace — Switch between Mermaid, PlantUML, Draw.io, and Mind Map modes in a single interface.
- AI Credits Add-On — Buy one-time credit packs for extra AI generation and premium model runs.
Use cases
- Generate quick flowcharts for documentation using Mermaid.
- Create formal UML class and component diagrams with PlantUML.
- Design freeform architecture diagrams via drag-and-drop Draw.io.
- Brainstorm project plans with AI-generated mind maps.
- Repair broken diagram code without manual debugging.
OnUml FAQ
What is OnUML?+
OnUML is an AI diagram generator and online editor that supports Mermaid, PlantUML, Draw.io, and mind-map workflows in one workspace.
Are there any usage limits?+
OnUML applies reasonable limits to keep the service stable; most regular users will not be affected.
What diagram types are supported?+
Four modes are supported: Mermaid, PlantUML, Draw.io, and Mind Map, each with its own set of diagram types.
How can I save my diagrams?+
Diagrams can be exported as PNG or SVG, and registered users can save them by project for later editing.
What is the difference between the four diagram modes?+
Mermaid is lightweight for docs, PlantUML handles formal UML, Draw.io offers freeform visual layouts, and Mind Map is for hierarchical brainstorming.
Is OnUML free?+
OnUML offers a Free plan with limits; Pro plans add capacity and AI credits, and additional credit packs are available for purchase.
Summarized by DevHunt from onuml.com · Oct 8, 2026. Details may change; check the official site.
