Modern Text-Based Diagramming: Why I Prefer Mermaid and PlantUML

In my earlier article (https://aajkyakaroon.blogspot.com/2019/04/free-visio-alternatives-in-linux-for.html), I explored graphical diagramming tools like Draw.io, yEd Graph Editor, and LibreOffice Draw as solid alternatives to Microsoft Visio, especially for Linux users. But over time, my approach to diagramming has evolved further toward text-based, code-driven tools—specifically Mermaid and PlantUML.

These tools bring immense benefits in flexibility, version control, and automation. Today, I want to share why they are now my go-to solutions, along with a practical example.

🌐 Why Text-Based Diagramming?

Traditional graphical diagramming tools are excellent for visual design, but they present challenges in these areas:

• Version Control: Tracking changes in binary or XML files is hard.
• Automation: Manually re-creating diagrams when data changes is cumbersome.
• Collaboration: Sharing diagrams requires complex file management.

Enter Mermaid and PlantUML: Both allow you to describe diagrams in simple text syntax. The diagrams are automatically rendered, making them perfect for integration into documentation, wikis, and codebases.

✅ Why I Use Mermaid

Mermaid is lightweight, web-friendly, and easy to integrate into Markdown or static site generators (like MkDocs or Hugo).

Example: Simple Flowchart in Mermaid

```mermaid
graph TD
    A[Start] --> B{Is it sunny?}
    B -- Yes --> C[Go for a walk]
    B -- No --> D[Stay indoors]
    C --> E[Have a picnic]
    D --> E[Read a book]
    E --> F[End]
```

graph TD A[Start] --> B{Is it sunny?} B -- Yes --> C[Go for a walk] B -- No --> D[Stay indoors] C --> E[Have a picnic] D --> E[Read a book] E --> F[End]

Key Advantages of Mermaid:

• Text files are easy to version-control (Git, etc.).
• Simple syntax is easy to learn.
• Integrated directly into Markdown and many static site generators.
• Generates SVG or PNG diagrams automatically.

🌟 Why I Also Use PlantUML

PlantUML is more powerful in terms of diagram variety and control. It supports:

• Sequence diagrams
• Class diagrams
• Component diagrams
• State diagrams

While its syntax is more verbose than Mermaid, PlantUML shines when detailed control and complex diagrams are needed.

Example Use Cases for PlantUML:

• Documenting API call flows
• Generating architecture diagrams directly from code
• Embedding diagrams in technical documentation

⚡ Updated Recommendation: Combine Both

Use Case	Recommended Tool
Simple process diagrams in Markdown	Mermaid
Sequence diagrams, class diagrams, architecture diagrams	PlantUML
Documentation with version control	Mermaid or PlantUML (text-based)
Automation from code	PlantUML (can integrate with build tools)

🌟 Conclusion – Code Meets Diagram

For anyone who values maintainability, reproducibility, and version control, I now strongly recommend using Mermaid and PlantUML as the modern alternatives to traditional diagramming tools.

These tools empower you to:

• Keep diagrams close to your documentation
• Automate updates as data changes
• Track every modification in your Git history

My current workflow combines Mermaid for lightweight, easy-to-write diagrams and PlantUML for structured, complex diagrams—helping me build clear, maintainable documentation efficiently.