How to convert PlantUML to Mermaid syntax online?

Paste your PlantUML diagram code into the left editor. The converter instantly translates it into standard Mermaid markdown and renders an interactive SVG diagram on the fly.

Is my diagram source code kept private?

Yes. All conversion logic and SVG rendering run 100% locally in your web browser. Zero diagram text or proprietary architecture data is ever transmitted to a server.

Why convert PlantUML diagrams into Mermaid?

Mermaid is supported natively in Markdown by GitHub, GitLab, Notion, Azure DevOps, and Obsidian without requiring a Java runtime environment or external Graphviz servers.

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PlantUML vs. Mermaid Syntax Cheat Sheet

Compare the differences between PlantUML formatting and Mermaid.js syntax for sequence and class diagrams:

Element Type	PlantUML	Mermaid Syntax
Diagram Header	`@startuml ... @enduml`	`sequenceDiagram` / `classDiagram`
Participant / Database	`database "User DB" as DB`	`participant DB as User DB`
Synchronous Request	`Client -> Server: Request`	`Client->>Server: Request`
Dotted Return	`Server --> Client: 200 OK`	`Server-->>Client: 200 OK`
Asynchronous Signal	`Producer ->> Queue: Push`	`Producer-)Queue: Push`
Class Inheritance	`ClassA <\|-- ClassB`	`ClassA <\|-- ClassB`

Frequently Asked Questions

Why migrate from PlantUML to Mermaid?

Mermaid is natively parsed by GitHub, GitLab, Notion, and Obsidian. Migrating eliminates the need to maintain Java runtimes, Graphviz binaries, or remote rendering servers.

Are my architecture diagrams sent to any server?

No. All parsing and SVG generation run entirely in your web browser. It is 100% private and safe for sensitive internal enterprise diagrams.