Comparison · 2025

Mermaid vs PlantUML

The two most popular diagram-as-code tools compared. Syntax, rendering, diagram types, ecosystem, and workflow. Use both in Cybewave Studio.

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Side-by-side comparison

Feature
Mermaid
PlantUML
Syntax style
Markdown-like, minimal
UML-based, verbose but precise
Rendering
JavaScript (browser-native)
Java server (requires JVM)
GitHub native
Yes — renders in .md files
No — needs external rendering
Diagram types
~15 types
~20+ types (deeper UML support)
C4 support
C4Context, C4Container, etc.
C4-PlantUML macros (full C4)
Sequence diagrams
Good — clean syntax
Excellent — most detailed
Class diagrams
Basic support
Full UML class diagrams
Learning curve
Low — intuitive syntax
Medium — UML notation
Customization
Themes, limited styling
Extensive skinparams
Ecosystem
Docusaurus, GitLab, Notion
Confluence, VS Code, CI tools

When to use which

Choose Mermaid when…

  • You want diagrams to render natively in GitHub README files
  • You need quick flowcharts, sequence diagrams, or architecture overviews
  • Your team prefers minimal, Markdown-like syntax
  • You're using Docusaurus, GitLab, or Notion for documentation

Choose PlantUML when…

  • You need detailed UML class, object, or activity diagrams
  • You want extensive style customization with skinparams
  • Your team is in a Java/enterprise ecosystem (Confluence, Jenkins)
  • You need diagram types Mermaid doesn't support (timing, wireframe)

Use Cybewave when…

  • You want both Mermaid AND PlantUML in one editor
  • You want AI to generate diagrams from descriptions
  • You need a unified workflow: edit → render → save → export
  • You want to switch between syntaxes per diagram type

Syntax comparison

Mermaid — Sequence diagram

sequenceDiagram
  Client->>API: POST /orders
  API->>DB: INSERT order
  DB-->>API: order_id
  API-->>Client: 201 Created

PlantUML — Sequence diagram

@startuml
Client -> API : POST /orders
API -> DB : INSERT order
DB --> API : order_id
API --> Client : 201 Created
@enduml

Explore more

Mermaid vs Cybewave

Cybewave extends Mermaid

PlantUML vs Cybewave

Cybewave extends PlantUML

Diagram as Code

Diagrams defined in code

Diagram as Code Tool

Best DaC tools compared

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