Mermaid Js Syntax

  • It's an htmlwidget for R. Create mermaid graphs. Use the shiny app to create graph specifications interactively.

  • Graphviz has quite the legacy for creating quality graphs. Now it's in DiagrammeR. Create graph specifications in the DOT language and take advantage of mixing R into it.

  • Change the way your diagram is rendered by taking advantage of all of these Graphviz engines: dot, neato, twopi, and circo.

  • An easier way to inject some R into your Graphviz graph specification. The @@ marks the spot for an evaluated R expression residing in the footnotes section.


  • Using mermaid, make Gantt charts. Define chunks of GraphvizDOT code using R data frames and new convenience functions.

  • A large selection of new functions for creating graph diagrams is now available. No need to interact directly with DOT code, just build diagrams in an R-like way.

  • Many more new functions were introduced to make it easier to inspect, analyze, and modify graphs.

  • Includes support for visNetwork graph rendering. More graph functions added, and, all functions optimized for piping.

Mermaid CLI Mermaid Diagrams on Hugo More. I have Grafana to thank for introducing me to Mermaid diagrams - one day at work a new Diagram widget appeared and naturally I had to explore further. What I found amazed me. If you are a fan of diagramming, markdown, and CLI tools - and have not heard of Mermaid, you are in for a treat! This is done by defining mermaid.sequenceConfig or by the CLI to use a json file with the configuration. How to use the CLI is described in the mermaidCLI page. Mermaid.sequenceConfig can be set to a JSON string with config parameters or the corresponding object.

Learn Mermaid.js

Mermaid Documentation

It is javascript framework for generating diagrams from text content. Text content is an in a syntax similar to markdown text. This project uses D3 and dagre-d3 libraries for graphics layout and drawing. This also has an online editor where you can design the diagrams and test it.

With this library can generate the following diagrams using javascript

  • FlowChart
  • Sequence Diagram
  • Gantt Diagram
  • Class Diagram
  • Git Graphs


Mermaid flowchart

No need for any commercial tools to generate flow and sequence diagram tools.
Simple tool to generate basic diagrams
Free to use
Online Editor to test text content.

Installation and Setup

This library can be used as javascript/jquery and node-based application

using CDN

Include CDN URL in script tag of HTML as like below

Using NodeJS npm

This installs dependencies in your nodejs application.

mermaidJS API usage

This will be used in client applications on the webpage to load it. These calls render function, parse the text syntax and Generate the diagram and output to SVN element In HTML, we will write HTML tag like this andsample-flowchart-example'>Sample Flowchart Example

Following snippet of code generates a simple flowchart diagram

Please see the output of this code as per screenshot

Mermaid CLI Usage

It is command line interface tool which takes mmd extension file as input and output to SVG, png and PDF format. mmd is a mermaid definition file which contains text markdown syntax formatted content. This has various options to configure, height, background color and css styles.
Install cli - using npm command, This installs tool globally

this cli provides mmdc command line option. you can check the usage and options as per below

Mermaid Js Syntax

Export to PDF/PNG/SVG example

This is an example of generating a sequence diagram from the text and convert into a png file and download it. Use a mmdc tool which accepts text file and generates a png file

you are also supplying width and height configuration for generated png file. sequence.mmd file contains below markdown text syntax


Mermaid Live Editor tool
This is online Editor tool to edit/preview/download mermaid flowcharts and diagrams. This will be very useful for coding mermaid definition file and test and preview the diagram flows. This will help developers to save time and debug if any issues. This has also various options like generate the link for the generated diagram and share it with others, Others can also edit the code and see the diagram. You can also download generated flow as SVG file.

Available Themes

  • Dark
  • Default
  • forest
  • neutral