Markdown-ish syntax for generating flowcharts, sequence diagrams, class diagrams, gantt charts and git graphs.
Mermaid is a JavaScript-based diagramming and charting tool that renders Markdown-inspired text definitions to create and dynamically modify diagrams. It is particularly useful for creating flowcharts, sequence diagrams, class diagrams, state diagrams, Gantt charts, and more.
Flowcharts
Mermaid allows you to create flowcharts using a simple syntax. The above code creates a flowchart with decision points and different paths.
```mermaid
flowchart TD
A[Start] --> B{Is it?}
B -->|Yes| C[OK]
B -->|No| D[Not OK]
C --> E[End]
D --> E[End]
```Sequence Diagrams
Sequence diagrams can be created to represent interactions between different participants over time. The code sample shows a simple interaction between Alice and Bob.
```mermaid
sequenceDiagram
participant Alice
participant Bob
Alice->>Bob: Hello Bob, how are you?
Bob-->>Alice: I am good thanks!
```Gantt Charts
Mermaid supports Gantt charts for project planning and scheduling. The code sample demonstrates how to define tasks and their durations.
```mermaid
gantt
title A Gantt Diagram
dateFormat YYYY-MM-DD
section Section
A task :a1, 2023-01-01, 30d
Another task :after a1 , 20d
section Another
Task in sec :2023-01-12 , 12d
another task : 24d
```Class Diagrams
Class diagrams can be used to represent the structure of a system by showing its classes, attributes, and methods. The code sample shows a simple class diagram with inheritance.
```mermaid
classDiagram
class Animal
Animal : +String name
Animal : +int age
Animal : +void eat()
Animal : +void sleep()
class Dog
Dog : +String breed
Dog : +void bark()
Animal <|-- Dog
```State Diagrams
State diagrams represent the states of an object and transitions between those states. The code sample shows a simple state diagram with different states and transitions.
```mermaid
stateDiagram-v2
[*] --> Still
Still --> [*]
Still --> Moving
Moving --> Still
Moving --> Crash
Crash --> [*]
```Flowchart.js is a simple library to create flowcharts using JavaScript. It is less feature-rich compared to Mermaid but is easier to use for basic flowchart needs.
js-sequence-diagrams is a library specifically for creating sequence diagrams. It offers a more focused approach to sequence diagrams but lacks the versatility of Mermaid.
Chart.js is a popular library for creating various types of charts and graphs. While it does not support diagrams like flowcharts or sequence diagrams, it excels in creating data-driven charts.
D3.js is a powerful library for creating complex and interactive data visualizations. It offers more flexibility and control compared to Mermaid but requires a steeper learning curve.
Generate diagrams from markdown-like text.
📖 Documentation | 🚀 Getting Started | 🌐 CDN | 🙌 Join Us
Try Live Editor previews of future releases: Develop | Next
:trophy: Mermaid was nominated and won the JS Open Source Awards (2019) in the category "The most exciting use of technology"!!!
Thanks to all involved, people committing pull requests, people answering questions! 🙏
Mermaid is a JavaScript-based diagramming and charting tool that uses Markdown-inspired text definitions and a renderer to create and modify complex diagrams. The main purpose of Mermaid is to help documentation catch up with development.
Doc-Rot is a Catch-22 that Mermaid helps to solve.
Diagramming and documentation costs precious developer time and gets outdated quickly.
But not having diagrams or docs ruins productivity and hurts organizational learning.
Mermaid addresses this problem by enabling users to create easily modifiable diagrams. It can also be made part of production scripts (and other pieces of code).
Mermaid allows even non-programmers to easily create detailed diagrams through the Mermaid Live Editor.
For video tutorials, visit our Tutorials page.
Use Mermaid with your favorite applications, check out the list of Integrations and Usages of Mermaid.
You can also use Mermaid within GitHub as well many of your other favorite applications—check out the list of Integrations and Usages of Mermaid.
For a more detailed introduction to Mermaid and some of its more basic uses, look to the Beginner's Guide, Usage and Tutorials.
In our release process we rely heavily on visual regression tests using applitools. Applitools is a great service which has been easy to use and integrate with our tests.
The following are some examples of the diagrams, charts and graphs that can be made using Mermaid. Click here to jump into the text syntax.
flowchart LR
A[Hard] -->|Text| B(Round)
B --> C{Decision}
C -->|One| D[Result 1]
C -->|Two| E[Result 2]
flowchart LR
A[Hard] -->|Text| B(Round)
B --> C{Decision}
C -->|One| D[Result 1]
C -->|Two| E[Result 2]
sequenceDiagram
Alice->>John: Hello John, how are you?
loop HealthCheck
John->>John: Fight against hypochondria
end
Note right of John: Rational thoughts!
John-->>Alice: Great!
John->>Bob: How about you?
Bob-->>John: Jolly good!
sequenceDiagram
Alice->>John: Hello John, how are you?
loop HealthCheck
John->>John: Fight against hypochondria
end
Note right of John: Rational thoughts!
John-->>Alice: Great!
John->>Bob: How about you?
Bob-->>John: Jolly good!
gantt
section Section
Completed :done, des1, 2014-01-06,2014-01-08
Active :active, des2, 2014-01-07, 3d
Parallel 1 : des3, after des1, 1d
Parallel 2 : des4, after des1, 1d
Parallel 3 : des5, after des3, 1d
Parallel 4 : des6, after des4, 1d
gantt
section Section
Completed :done, des1, 2014-01-06,2014-01-08
Active :active, des2, 2014-01-07, 3d
Parallel 1 : des3, after des1, 1d
Parallel 2 : des4, after des1, 1d
Parallel 3 : des5, after des3, 1d
Parallel 4 : des6, after des4, 1d
classDiagram
Class01 <|-- AveryLongClass : Cool
<<Interface>> Class01
Class09 --> C2 : Where am I?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class01 : size()
Class01 : int chimp
Class01 : int gorilla
class Class10 {
<<service>>
int id
size()
}
classDiagram
Class01 <|-- AveryLongClass : Cool
<<Interface>> Class01
Class09 --> C2 : Where am I?
Class09 --* C3
Class09 --|> Class07
Class07 : equals()
Class07 : Object[] elementData
Class01 : size()
Class01 : int chimp
Class01 : int gorilla
class Class10 {
<<service>>
int id
size()
}
stateDiagram-v2
[*] --> Still
Still --> [*]
Still --> Moving
Moving --> Still
Moving --> Crash
Crash --> [*]
stateDiagram-v2
[*] --> Still
Still --> [*]
Still --> Moving
Moving --> Still
Moving --> Crash
Crash --> [*]
pie
"Dogs" : 386
"Cats" : 85.9
"Rats" : 15
pie
"Dogs" : 386
"Cats" : 85.9
"Rats" : 15
gantt
title Git Issues - days since last update
dateFormat X
axisFormat %s
section Issue19062
71 : 0, 71
section Issue19401
36 : 0, 36
section Issue193
34 : 0, 34
section Issue7441
9 : 0, 9
section Issue1300
5 : 0, 5
gantt
title Git Issues - days since last update
dateFormat X
axisFormat %s
section Issue19062
71 : 0, 71
section Issue19401
36 : 0, 36
section Issue193
34 : 0, 34
section Issue7441
9 : 0, 9
section Issue1300
5 : 0, 5
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: 3: Me
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: 3: Me
C4Context
title System Context diagram for Internet Banking System
Person(customerA, "Banking Customer A", "A customer of the bank, with personal bank accounts.")
Person(customerB, "Banking Customer B")
Person_Ext(customerC, "Banking Customer C")
System(SystemAA, "Internet Banking System", "Allows customers to view information about their bank accounts, and make payments.")
Person(customerD, "Banking Customer D", "A customer of the bank, <br/> with personal bank accounts.")
Enterprise_Boundary(b1, "BankBoundary") {
SystemDb_Ext(SystemE, "Mainframe Banking System", "Stores all of the core banking information about customers, accounts, transactions, etc.")
System_Boundary(b2, "BankBoundary2") {
System(SystemA, "Banking System A")
System(SystemB, "Banking System B", "A system of the bank, with personal bank accounts.")
}
System_Ext(SystemC, "E-mail system", "The internal Microsoft Exchange e-mail system.")
SystemDb(SystemD, "Banking System D Database", "A system of the bank, with personal bank accounts.")
Boundary(b3, "BankBoundary3", "boundary") {
SystemQueue(SystemF, "Banking System F Queue", "A system of the bank, with personal bank accounts.")
SystemQueue_Ext(SystemG, "Banking System G Queue", "A system of the bank, with personal bank accounts.")
}
}
BiRel(customerA, SystemAA, "Uses")
BiRel(SystemAA, SystemE, "Uses")
Rel(SystemAA, SystemC, "Sends e-mails", "SMTP")
Rel(SystemC, customerA, "Sends e-mails to")
C4Context
title System Context diagram for Internet Banking System
Person(customerA, "Banking Customer A", "A customer of the bank, with personal bank accounts.")
Person(customerB, "Banking Customer B")
Person_Ext(customerC, "Banking Customer C")
System(SystemAA, "Internet Banking System", "Allows customers to view information about their bank accounts, and make payments.")
Person(customerD, "Banking Customer D", "A customer of the bank, <br/> with personal bank accounts.")
Enterprise_Boundary(b1, "BankBoundary") {
SystemDb_Ext(SystemE, "Mainframe Banking System", "Stores all of the core banking information about customers, accounts, transactions, etc.")
System_Boundary(b2, "BankBoundary2") {
System(SystemA, "Banking System A")
System(SystemB, "Banking System B", "A system of the bank, with personal bank accounts.")
}
System_Ext(SystemC, "E-mail system", "The internal Microsoft Exchange e-mail system.")
SystemDb(SystemD, "Banking System D Database", "A system of the bank, with personal bank accounts.")
Boundary(b3, "BankBoundary3", "boundary") {
SystemQueue(SystemF, "Banking System F Queue", "A system of the bank, with personal bank accounts.")
SystemQueue_Ext(SystemG, "Banking System G Queue", "A system of the bank, with personal bank accounts.")
}
}
BiRel(customerA, SystemAA, "Uses")
BiRel(SystemAA, SystemE, "Uses")
Rel(SystemAA, SystemC, "Sends e-mails", "SMTP")
Rel(SystemC, customerA, "Sends e-mails to")
For those who have the permission to do so:
Update version number in package.json.
npm publish
The above command generates files into the dist folder and publishes them to https://www.npmjs.com.
Mermaid is a growing community and is always accepting new contributors. There's a lot of different ways to help out and we're always looking for extra hands! Look at this issue if you want to know where to start helping out.
Detailed information about how to contribute can be found in the contribution guide
For public sites, it can be precarious to retrieve text from users on the internet, storing that content for presentation in a browser at a later stage. The reason is that the user content can contain embedded malicious scripts that will run when the data is presented. For Mermaid this is a risk, specially as mermaid diagrams contain many characters that are used in html which makes the standard sanitation unusable as it also breaks the diagrams. We still make an effort to sanitize the incoming code and keep refining the process but it is hard to guarantee that there are no loop holes.
As an extra level of security for sites with external users we are happy to introduce a new security level in which the diagram is rendered in a sandboxed iframe preventing javascript in the code from being executed. This is a great step forward for better security.
Unfortunately you can not have a cake and eat it at the same time which in this case means that some of the interactive functionality gets blocked along with the possible malicious code.
To report a vulnerability, please e-mail security@mermaid.live with a description of the issue, the steps you took to create the issue, affected versions, and if known, mitigations for the issue.
A quick note from Knut Sveidqvist:
Many thanks to the d3 and dagre-d3 projects for providing the graphical layout and drawing libraries!
Thanks also to the js-sequence-diagram project for usage of the grammar for the sequence diagrams. Thanks to Jessica Peter for inspiration and starting point for gantt rendering.
Thank you to Tyler Long who has been a collaborator since April 2017.
Thank you to the ever-growing list of contributors that brought the project this far!
Mermaid was created by Knut Sveidqvist for easier documentation.
FAQs
Markdown-ish syntax for generating flowcharts, mindmaps, sequence diagrams, class diagrams, gantt charts, git graphs and more.
The npm package mermaid receives a total of 812,839 weekly downloads. As such, mermaid popularity was classified as popular.
We found that mermaid demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 5 open source maintainers collaborating on the project.
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