PlantUML Editor uml.singsk.com

A software tool online that lets you edit PlantUML syntax code and produce a diagram. Type PlantUML on the left, see the SVG/PNG diagram live on the right, share it with a URL. Fully AI-first.

What it does

• Edit PlantUML syntax code in the browser — highlighting, autocomplete, code folding
• Render to SVG or PNG live while you type (official PlantUML engine)
• Pan/zoom the diagram; your view and layout are remembered across reloads
• Share or API-call any diagram via its render URL; encode/decode PlantUML URL tokens
• 22 diagram types documented locally in the syntax reference

AI-first

AI agents can operate the entire tool with no human walkthrough:

• Discovery document: /api/
• OpenAPI 3.0: /api/openapi.json
• Swagger UI: /api/docs
• llms.txt: /llms.txt
• MCP server (native tools): https://uml.singsk.com/mcp — manifest at /.well-known/mcp.json; listed in the official MCP Registry as com.singsk/uml-plantuml
• Self-correction: POST /api/validate returns machine-readable errors with line numbers and hints

AI Assistant — an in-editor assistant (natural language → PlantUML) is in development and not published yet. Coming soon.

Try it from any terminal — PlantUML code in, diagram out:

curl -X POST https://uml.singsk.com/api/render \
  -H "Content-Type: application/json" \
  -d '{"text":"@startuml\nAlice -> Bob: hello\n@enduml","format":"svg"}' \
  -o diagram.svg

Security

Found a security issue? Please report it responsibly — see /.well-known/security.txt (RFC 9116) or write to security@singsk.com. The service is anonymous and stores no accounts or personal data; diagrams travel as self-contained encoded URLs.

uml.singsk.com is part of the SingSK family, alongside ai.singsk.com — the SingSK AI workspace where agents generate diagrams through this very API. See the full usage guide for diagram-as-code, sharing and automation.

Open the editor Syntax help Usage guide

#PlantUML #PlantUML-Editor #Diagram-As-Code #UML #SVG #AI-First

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