Have you ever needed a quick way to sketch a flowchart, draw a class diagram, or visualize a project timeline without leaving your text editor? Enter Mermaid — an elegant, code-based diagramming and charting tool that integrates directly into Markdown and supports a wide range of visualization types.
Whether you’re documenting code, mapping infrastructure, or teaching concepts, Mermaid lets you create diagrams using text-based syntax — making it easy to version, share, and update visuals alongside your content.
🔧 What is Mermaid? Mermaid is a JavaScript-based tool that transforms plaintext into beautiful diagrams. Its lightweight syntax is designed to be easy to write and readable, even when embedded inside Markdown files.
Mermaid is ideal for:
- Developers and engineers writing docs
- Product managers creating workflows
- Educators explaining systems
- Anyone using Markdown or static site generators
✍️ Getting Started with Mermaid Syntax Mermaid diagrams are written inside code blocks with the mermaid tag:
graph TD
A[Start] --> B{Decision}
B -->|Yes| C[End]
B -->|No| D[Keep Going]
This renders as a flowchart (we’ll show a live preview later in your tool).
🔌 Mermaid VS Code Plugin To make editing even easier, install the Mermaid Preview or Markdown Preview Mermaid Support extension in Visual Studio Code:
📦 Steps:
- Open VS Code.
- Go to Extensions (Ctrl+Shift+X or Cmd+Shift+X).
- Search for Mermaid Preview or Markdown Preview Mermaid Support.
- Click Install.
Open a .md file with Mermaid code blocks and click Open Preview (Ctrl+K V).
These plugins give you real-time previews, syntax highlighting, and export options.
📚 Examples of Mermaid Diagram Types
- Flowchart Great for general processes and logic flows.
graph LR
Start --> Step1[Do something]
Step1 --> Step2{Was it successful?}
Step2 -- Yes --> Done[Great!]
Step2 -- No --> Retry[Try again]
Retry --> Step1
- Sequence Diagram Perfect for modeling interactions between systems or actors.
sequenceDiagram
participant User
participant App
participant DB
User->>App: Login
App->>DB: Verify credentials
DB-->>App: OK
App-->>User: Success- Gantt Chart Useful for project timelines and planning.
gantt
title Project Timeline
dateFormat YYYY-MM-DD
section Development
Setup :done, setup, 2024-01-01, 3d
Feature A :active, a1, 2024-01-04, 5d
Feature B : a2, after a1, 4d
QA Testing : test1, after a2, 3d
- Class Diagram Model classes and object-oriented structures.
classDiagram
class Animal {
+String name
+move()
}
class Dog {
+bark()
}
Animal <|-- Dog- State Diagram Good for modeling state machines.
stateDiagram
[*] --> Idle
Idle --> Loading : Start load
Loading --> Success : Load complete
Loading --> Error : Load failed
Error --> Idle : Retry
- Entity-Relationship (ER) Diagram Great for data modeling and database structure.
erDiagram
CUSTOMER ||--o{ ORDER : places
ORDER ||--|{ LINE_ITEM : contains
CUSTOMER {
string name
string address
}
ORDER {
int orderNumber
date orderDate
}
- Pie Chart Simple way to visualize proportions.
pie
title Project Breakdown
"Frontend" : 40
"Backend" : 30
"Testing" : 20
"Deployment" : 10
✅ Mermaid in Markdown: Where It Works Mermaid diagrams can be rendered in many environments:
GitHub (yes, it now supports Mermaid in Markdown!)
Obsidian
MkDocs (Material theme)
Docsify / VuePress / Docusaurus
Static Site Generators
Notion (via embeds or plugins)
🧠 Pro Tips Use Mermaid Live Editor to test and tweak your diagrams interactively.
Use %% comments in Mermaid blocks to document your diagram.
Combine Mermaid with Git for version control on both diagrams and docs.
Export diagrams from the Mermaid Live Editor or VS Code plugin as SVG or PNG.
💬 Final Thoughts Mermaid empowers you to communicate visually without needing a design tool. Whether you’re illustrating a user journey, mapping a backend service, or writing a technical tutorial — Mermaid helps you do it clearly, consistently, and beautifully, all from within your Markdown files or VS Code editor.