OnUML
API—OSS—FREE—DOCS2/5
ON5.0#28 of 32
outWeb—Windows—Mac—Linux—Android—iOS
Ranked in AI Diagram Generators ·Free plan· paid from $8/mo
About
OnUML is ranked #28 of 32 in AI diagram generators on Inferse. It runs on API, Web. There is a free plan. Paid plans start at $8/mo.
Compared on AI diagram generators
Facts
- Product
- OnUML is an AI diagram generator and online UML editor for Mermaid, PlantUML, Draw.io, and mind maps.onuml.com · 9 Oct 2026
- Generation
- It generates diagrams from natural-language prompts and supported image inputs.onuml.com · 9 Oct 2026
- Editing
- Users can edit diagrams visually or through code and preview changes in real time.onuml.com · 9 Oct 2026
- AI repair
- The editor offers one-click repair for Mermaid and PlantUML syntax errors.onuml.com · 9 Oct 2026
- History and organization
- Users can save multiple code versions, restore earlier content, and organize diagrams by project.onuml.com · 9 Oct 2026
- Export and sharing
- OnUML supports PNG and SVG export and shareable links.onuml.com · 9 Oct 2026
- Integrations
- Its remote MCP server connects to coding agents including Codex, Claude Code, Cursor, and OpenClaw.onuml.com · 9 Oct 2026
- MCP access
- The MCP server follows the signed-in account’s workspace permissions and supports reading and updating Mermaid, PlantUML, and OnUML mind maps; Draw.io is not supported through MCP.onuml.com · 9 Oct 2026
- MCP safeguards
- OnUML says MCP updates check the latest diagram before changing it and stop if newer edits would be overwritten; retries are designed not to duplicate project or diagram creation.onuml.com · 9 Oct 2026
- Usage limits
- The free plan allows 2 diagrams per project, 10 cloud projects per workspace, 2 workspaces, and 10 free model requests per day.onuml.com · 9 Oct 2026
- Credit limits
- Purchased AI credits expire 6 months after issuance and do not unlock diagram, project, or workspace capacity.onuml.com · 9 Oct 2026
- Support
- The site lists [email protected] as its contact email.onuml.com · 9 Oct 2026
- Operator
- The site says OnUML is a product operated by myun L.L.C.onuml.com · 9 Oct 2026
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Where it ranks on Inferse
- Best AI Diagram Generators in 2026#28 of 32
Sources
- onuml.com· checked 9 Oct 2026
- onuml.com/mcp-guide· checked 9 Oct 2026