David Simpson Apps

Mermaid Diagram Syntax

Mermaid is a tool that lets you create complicated diagrams in Markdown — it works with simple commands and an intuitive syntax. You don't have to draw anything, just write down what you want to see.

You can create flowcharts to help you understand algorithms, Gantt charts for project management, pie charts, and many other common diagram types.

Flowchart

graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;

Sequence diagram

sequenceDiagram
    participant Alice
    participant Bob
    Alice->>John: Hello John, how are you?
    loop Healthcheck
        John->>John: Fight against hypochondria
    end
    Note right of John: Rational thoughts prevail!
    John-->>Alice: Great!
    John->>Bob: How about you?
    Bob-->>John: Jolly good!

Gantt diagram

gantt
dateFormat  YYYY-MM-DD
title Adding GANTT diagram to mermaid
excludes weekdays 2014-01-10

section A section
Completed task            :done,    des1, 2014-01-06,2014-01-08
Active task               :active,  des2, 2014-01-09, 3d
Future task               :         des3, after des2, 5d
Future task2              :         des4, after des3, 5d

Class diagram

classDiagram
Class01 <|-- AveryLongClass : Cool
Class03 *-- Class04
Class05 o-- Class06
Class07 .. Class08
Class09 --> C2 : Where am i?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class01 : size()
Class01 : int chimp
Class01 : int gorilla
Class08 <--> C2: Cool label

Git diagram

gitGraph
       commit
       commit
       branch develop
       commit
       commit
       commit
       checkout main
       commit
       commit

Entity relationship diagram

CUSTOMER ||--o{ ORDER : places
ORDER ||--|{ LINE-ITEM : contains
CUSTOMER }|..|{ DELIVERY-ADDRESS : uses

User journey diagram

journey
    title My working day
    section Go to work
      Make tea: 5: Me
      Go upstairs: 3: Me
      Do work: 1: Me, Cat
    section Go home
      Go downstairs: 5: Me
      Sit down: 5: Me