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Flowcharts - Basic Syntax
Flowcharts are composed of nodes (geometric shapes) and edges (arrows or lines). The Mermaid code defines how nodes and edges are made and accommodates different arrow types, multi-directional arrows, and any linking to and from subgraphs.
Warning
If you are using the word "end" in a Flowchart node, capitalize the entire word or any of the letters (e.g., "End" or "END"), or apply this workaround. Typing "end" in all lowercase letters will break the Flowchart.
Warning
If you are using the letter "o" or "x" as the first letter in a connecting Flowchart node, add a space before the letter or capitalize the letter (e.g., "dev--- ops", "dev---Ops").
Typing "A---oB" will create a circle edge.
Typing "A---xB" will create a cross edge.
A node (default)
---
title: Node
---
flowchart LR
id
---
title: Node
---
flowchart LR
id
Note
The id is what is displayed in the box.
💡 Tip Instead of
flowchart
one can also usegraph
.
A node with text
It is also possible to set text in the box that differs from the id. If this is done several times, it is the last text found for the node that will be used. Also if you define edges for the node later on, you can omit text definitions. The one previously defined will be used when rendering the box.
---
title: Node with text
---
flowchart LR
id1[This is the text in the box]
---
title: Node with text
---
flowchart LR
id1[This is the text in the box]
Unicode text
Use "
to enclose the unicode text.
flowchart LR
id["This ❤ Unicode"]
flowchart LR
id["This ❤ Unicode"]
Markdown formatting
Use double quotes and backticks "` text `" to enclose the markdown text.
%%{init: {"flowchart": {"htmlLabels": false}} }%%
flowchart LR
markdown["`This **is** _Markdown_`"]
newLines["`Line1
Line 2
Line 3`"]
markdown --> newLines
%%{init: {"flowchart": {"htmlLabels": false}} }%%
flowchart LR
markdown["`This **is** _Markdown_`"]
newLines["`Line1
Line 2
Line 3`"]
markdown --> newLines
Direction
This statement declares the direction of the Flowchart.
This declares the flowchart is oriented from top to bottom (TD
or TB
).
flowchart TD
Start --> Stop
flowchart TD
Start --> Stop
This declares the flowchart is oriented from left to right (LR
).
flowchart LR
Start --> Stop
flowchart LR
Start --> Stop
Possible FlowChart orientations are:
- TB - Top to bottom
- TD - Top-down/ same as top to bottom
- BT - Bottom to top
- RL - Right to left
- LR - Left to right
Node shapes
A node with round edges
flowchart LR
id1(This is the text in the box)
flowchart LR
id1(This is the text in the box)
A stadium-shaped node
flowchart LR
id1([This is the text in the box])
flowchart LR
id1([This is the text in the box])
A node in a subroutine shape
flowchart LR
id1[[This is the text in the box]]
flowchart LR
id1[[This is the text in the box]]
A node in a cylindrical shape
flowchart LR
id1[(Database)]
flowchart LR
id1[(Database)]
A node in the form of a circle
flowchart LR
id1((This is the text in the circle))
flowchart LR
id1((This is the text in the circle))
A node in an asymmetric shape
flowchart LR
id1>This is the text in the box]
flowchart LR
id1>This is the text in the box]
Currently only the shape above is possible and not its mirror. This might change with future releases.
A node (rhombus)
flowchart LR
id1{This is the text in the box}
flowchart LR
id1{This is the text in the box}
A hexagon node
flowchart LR
id1{{This is the text in the box}}
flowchart LR
id1{{This is the text in the box}}
Parallelogram
flowchart TD
id1[/This is the text in the box/]
flowchart TD
id1[/This is the text in the box/]
Parallelogram alt
flowchart TD
id1[\This is the text in the box\]
flowchart TD
id1[\This is the text in the box\]
Trapezoid
flowchart TD
A[/Christmas\]
flowchart TD
A[/Christmas\]
Trapezoid alt
flowchart TD
B[\Go shopping/]
flowchart TD
B[\Go shopping/]
Double circle
flowchart TD
id1(((This is the text in the circle)))
flowchart TD
id1(((This is the text in the circle)))
Expanded Node Shapes in Mermaid Flowcharts (v11.3.0+)
Mermaid introduces 30 new shapes to enhance the flexibility and precision of flowchart creation. These new shapes provide more options to represent processes, decisions, events, data storage visually, and other elements within your flowcharts, improving clarity and semantic meaning.
New Syntax for Shape Definition
Mermaid now supports a general syntax for defining shape types to accommodate the growing number of shapes. This syntax allows you to assign specific shapes to nodes using a clear and flexible format:
A@{ shape: rect }
This syntax creates a node A as a rectangle. It renders in the same way as A["A"]
, or A
.
Complete List of New Shapes
Below is a comprehensive list of the newly introduced shapes and their corresponding semantic meanings, short names, and aliases:
Semantic Name | Shape Name | Short Name | Description | Alias Supported |
---|---|---|---|---|
Card | Notched Rectangle | notch-rect |
Represents a card | card , notched-rectangle |
Collate | Hourglass | hourglass |
Represents a collate operation | collate , hourglass |
Com Link | Lightning Bolt | bolt |
Communication link | com-link , lightning-bolt |
Comment | Curly Brace | brace |
Adds a comment | brace-l , comment |
Comment Right | Curly Brace | brace-r |
Adds a comment | |
Comment with braces on both sides | Curly Braces | braces |
Adds a comment | |
Data Input/Output | Lean Right | lean-r |
Represents input or output | in-out , lean-right |
Data Input/Output | Lean Left | lean-l |
Represents output or input | lean-left , out-in |
Database | Cylinder | cyl |
Database storage | cylinder , database , db |
Decision | Diamond | diam |
Decision-making step | decision , diamond , question |
Delay | Half-Rounded Rectangle | delay |
Represents a delay | half-rounded-rectangle |
Direct Access Storage | Horizontal Cylinder | h-cyl |
Direct access storage | das , horizontal-cylinder |
Disk Storage | Lined Cylinder | lin-cyl |
Disk storage | disk , lined-cylinder |
Display | Curved Trapezoid | curv-trap |
Represents a display | curved-trapezoid , display |
Divided Process | Divided Rectangle | div-rect |
Divided process shape | div-proc , divided-process , divided-rectangle |
Document | Document | doc |
Represents a document | doc , document |
Event | Rounded Rectangle | rounded |
Represents an event | event |
Extract | Triangle | tri |
Extraction process | extract , triangle |
Fork/Join | Filled Rectangle | fork |
Fork or join in process flow | join |
Internal Storage | Window Pane | win-pane |
Internal storage | internal-storage , window-pane |
Junction | Filled Circle | f-circ |
Junction point | filled-circle , junction |
Lined Document | Lined Document | lin-doc |
Lined document | lined-document |
Lined/Shaded Process | Lined Rectangle | lin-rect |
Lined process shape | lin-proc , lined-process , lined-rectangle , shaded-process |
Loop Limit | Trapezoidal Pentagon | notch-pent |
Loop limit step | loop-limit , notched-pentagon |
Manual File | Flipped Triangle | flip-tri |
Manual file operation | flipped-triangle , manual-file |
Manual Input | Sloped Rectangle | sl-rect |
Manual input step | manual-input , sloped-rectangle |
Manual Operation | Trapezoid Base Top | trap-t |
Represents a manual task | inv-trapezoid , manual , trapezoid-top |
Multi-Document | Stacked Document | docs |
Multiple documents | documents , st-doc , stacked-document |
Multi-Process | Stacked Rectangle | st-rect |
Multiple processes | processes , procs , stacked-rectangle |
Odd | Odd | odd |
Odd shape | |
Paper Tape | Flag | flag |
Paper tape | paper-tape |
Prepare Conditional | Hexagon | hex |
Preparation or condition step | hexagon , prepare |
Priority Action | Trapezoid Base Bottom | trap-b |
Priority action | priority , trapezoid , trapezoid-bottom |
Process | Rectangle | rect |
Standard process shape | proc , process , rectangle |
Start | Circle | circle |
Starting point | circ |
Start | Small Circle | sm-circ |
Small starting point | small-circle , start |
Stop | Double Circle | dbl-circ |
Represents a stop point | double-circle |
Stop | Framed Circle | fr-circ |
Stop point | framed-circle , stop |
Stored Data | Bow Tie Rectangle | bow-rect |
Stored data | bow-tie-rectangle , stored-data |
Subprocess | Framed Rectangle | fr-rect |
Subprocess | framed-rectangle , subproc , subprocess , subroutine |
Summary | Crossed Circle | cross-circ |
Summary | crossed-circle , summary |
Tagged Document | Tagged Document | tag-doc |
Tagged document | tag-doc , tagged-document |
Tagged Process | Tagged Rectangle | tag-rect |
Tagged process | tag-proc , tagged-process , tagged-rectangle |
Terminal Point | Stadium | stadium |
Terminal point | pill , terminal |
Text Block | Text Block | text |
Text block |
Example Flowchart with New Shapes
Here’s an example flowchart that utilizes some of the newly introduced shapes:
flowchart RL
A@{ shape: manual-file, label: "File Handling"}
B@{ shape: manual-input, label: "User Input"}
C@{ shape: docs, label: "Multiple Documents"}
D@{ shape: procs, label: "Process Automation"}
E@{ shape: paper-tape, label: "Paper Records"}
flowchart RL
A@{ shape: manual-file, label: "File Handling"}
B@{ shape: manual-input, label: "User Input"}
C@{ shape: docs, label: "Multiple Documents"}
D@{ shape: procs, label: "Process Automation"}
E@{ shape: paper-tape, label: "Paper Records"}
Process
flowchart TD
A@{ shape: rect, label: "This is a process" }
flowchart TD
A@{ shape: rect, label: "This is a process" }
Event
flowchart TD
A@{ shape: rounded, label: "This is an event" }
flowchart TD
A@{ shape: rounded, label: "This is an event" }
Terminal Point (Stadium)
flowchart TD
A@{ shape: stadium, label: "Terminal point" }
flowchart TD
A@{ shape: stadium, label: "Terminal point" }
Subprocess
flowchart TD
A@{ shape: subproc, label: "This is a subprocess" }
flowchart TD
A@{ shape: subproc, label: "This is a subprocess" }
Database (Cylinder)
flowchart TD
A@{ shape: cyl, label: "Database" }
flowchart TD
A@{ shape: cyl, label: "Database" }
Start (Circle)
flowchart TD
A@{ shape: circle, label: "Start" }
flowchart TD
A@{ shape: circle, label: "Start" }
Odd
flowchart TD
A@{ shape: odd, label: "Odd shape" }
flowchart TD
A@{ shape: odd, label: "Odd shape" }
Decision (Diamond)
flowchart TD
A@{ shape: diamond, label: "Decision" }
flowchart TD
A@{ shape: diamond, label: "Decision" }
Prepare Conditional (Hexagon)
flowchart TD
A@{ shape: hex, label: "Prepare conditional" }
flowchart TD
A@{ shape: hex, label: "Prepare conditional" }
Data Input/Output (Lean Right)
flowchart TD
A@{ shape: lean-r, label: "Input/Output" }
flowchart TD
A@{ shape: lean-r, label: "Input/Output" }
Data Input/Output (Lean Left)
flowchart TD
A@{ shape: lean-l, label: "Output/Input" }
flowchart TD
A@{ shape: lean-l, label: "Output/Input" }
Priority Action (Trapezoid Base Bottom)
flowchart TD
A@{ shape: trap-b, label: "Priority action" }
flowchart TD
A@{ shape: trap-b, label: "Priority action" }
Manual Operation (Trapezoid Base Top)
flowchart TD
A@{ shape: trap-t, label: "Manual operation" }
flowchart TD
A@{ shape: trap-t, label: "Manual operation" }
Stop (Double Circle)
flowchart TD
A@{ shape: dbl-circ, label: "Stop" }
flowchart TD
A@{ shape: dbl-circ, label: "Stop" }
Text Block
flowchart TD
A@{ shape: text, label: "This is a text block" }
flowchart TD
A@{ shape: text, label: "This is a text block" }
Card (Notched Rectangle)
flowchart TD
A@{ shape: notch-rect, label: "Card" }
flowchart TD
A@{ shape: notch-rect, label: "Card" }
Lined/Shaded Process
flowchart TD
A@{ shape: lin-rect, label: "Lined process" }
flowchart TD
A@{ shape: lin-rect, label: "Lined process" }
Start (Small Circle)
flowchart TD
A@{ shape: sm-circ, label: "Small start" }
flowchart TD
A@{ shape: sm-circ, label: "Small start" }
Stop (Framed Circle)
flowchart TD
A@{ shape: framed-circle, label: "Stop" }
flowchart TD
A@{ shape: framed-circle, label: "Stop" }
Fork/Join (Long Rectangle)
flowchart TD
A@{ shape: fork, label: "Fork or Join" }
flowchart TD
A@{ shape: fork, label: "Fork or Join" }
Collate (Hourglass)
flowchart TD
A@{ shape: hourglass, label: "Collate" }
flowchart TD
A@{ shape: hourglass, label: "Collate" }
Comment (Curly Brace)
flowchart TD
A@{ shape: comment, label: "Comment" }
flowchart TD
A@{ shape: comment, label: "Comment" }
Comment Right (Curly Brace Right)
flowchart TD
A@{ shape: brace-r, label: "Comment" }
flowchart TD
A@{ shape: brace-r, label: "Comment" }
Comment with braces on both sides
flowchart TD
A@{ shape: braces, label: "Comment" }
flowchart TD
A@{ shape: braces, label: "Comment" }
Com Link (Lightning Bolt)
flowchart TD
A@{ shape: bolt, label: "Communication link" }
flowchart TD
A@{ shape: bolt, label: "Communication link" }
Document
flowchart TD
A@{ shape: doc, label: "Document" }
flowchart TD
A@{ shape: doc, label: "Document" }
Delay (Half-Rounded Rectangle)
flowchart TD
A@{ shape: delay, label: "Delay" }
flowchart TD
A@{ shape: delay, label: "Delay" }
Direct Access Storage (Horizontal Cylinder)
flowchart TD
A@{ shape: das, label: "Direct access storage" }
flowchart TD
A@{ shape: das, label: "Direct access storage" }
Disk Storage (Lined Cylinder)
flowchart TD
A@{ shape: lin-cyl, label: "Disk storage" }
flowchart TD
A@{ shape: lin-cyl, label: "Disk storage" }
Display (Curved Trapezoid)
flowchart TD
A@{ shape: curv-trap, label: "Display" }
flowchart TD
A@{ shape: curv-trap, label: "Display" }
Divided Process (Divided Rectangle)
flowchart TD
A@{ shape: div-rect, label: "Divided process" }
flowchart TD
A@{ shape: div-rect, label: "Divided process" }
Extract (Small Triangle)
flowchart TD
A@{ shape: tri, label: "Extract" }
flowchart TD
A@{ shape: tri, label: "Extract" }
Internal Storage (Window Pane)
flowchart TD
A@{ shape: win-pane, label: "Internal storage" }
flowchart TD
A@{ shape: win-pane, label: "Internal storage" }
Junction (Filled Circle)
flowchart TD
A@{ shape: f-circ, label: "Junction" }
flowchart TD
A@{ shape: f-circ, label: "Junction" }
Lined Document
flowchart TD
A@{ shape: lin-doc, label: "Lined document" }
flowchart TD
A@{ shape: lin-doc, label: "Lined document" }
Loop Limit (Notched Pentagon)
flowchart TD
A@{ shape: notch-pent, label: "Loop limit" }
flowchart TD
A@{ shape: notch-pent, label: "Loop limit" }
Manual File (Flipped Triangle)
flowchart TD
A@{ shape: flip-tri, label: "Manual file" }
flowchart TD
A@{ shape: flip-tri, label: "Manual file" }
Manual Input (Sloped Rectangle)
flowchart TD
A@{ shape: sl-rect, label: "Manual input" }
flowchart TD
A@{ shape: sl-rect, label: "Manual input" }
Multi-Document (Stacked Document)
flowchart TD
A@{ shape: docs, label: "Multiple documents" }
flowchart TD
A@{ shape: docs, label: "Multiple documents" }
Multi-Process (Stacked Rectangle)
flowchart TD
A@{ shape: processes, label: "Multiple processes" }
flowchart TD
A@{ shape: processes, label: "Multiple processes" }
Paper Tape (Flag)
flowchart TD
A@{ shape: flag, label: "Paper tape" }
flowchart TD
A@{ shape: flag, label: "Paper tape" }
Stored Data (Bow Tie Rectangle)
flowchart TD
A@{ shape: bow-rect, label: "Stored data" }
flowchart TD
A@{ shape: bow-rect, label: "Stored data" }
Summary (Crossed Circle)
flowchart TD
A@{ shape: cross-circ, label: "Summary" }
flowchart TD
A@{ shape: cross-circ, label: "Summary" }
Tagged Document
flowchart TD
A@{ shape: tag-doc, label: "Tagged document" }
flowchart TD
A@{ shape: tag-doc, label: "Tagged document" }
Tagged Process (Tagged Rectangle)
flowchart TD
A@{ shape: tag-rect, label: "Tagged process" }
flowchart TD
A@{ shape: tag-rect, label: "Tagged process" }
Special shapes in Mermaid Flowcharts (v11.3.0+)
Mermaid also introduces 2 special shapes to enhance your flowcharts: icon and image. These shapes allow you to include icons and images directly within your flowcharts, providing more visual context and clarity.
Icon Shape
You can use the icon
shape to include an icon in your flowchart. To use icons, you need to register the icon pack first. Follow the instructions provided here. The syntax for defining an icon shape is as follows:
flowchart TD
A@{ icon: "fa:user", form: "square", label: "User Icon", pos: "t", h: 60 }
flowchart TD
A@{ icon: "fa:user", form: "square", label: "User Icon", pos: "t", h: 60 }
Parameters
- icon: The name of the icon from the registered icon pack.
- form: Specifies the background shape of the icon. If not defined there will be no background to icon. Options include:
square
circle
rounded
- label: The text label associated with the icon. This can be any string. If not defined, no label will be displayed.
- pos: The position of the label. If not defined label will default to bottom of icon. Possible values are:
t
b
- h: The height of the icon. If not defined this will default to 48 which is minimum.
Image Shape
You can use the image
shape to include an image in your flowchart. The syntax for defining an image shape is as follows:
flowchart TD
A@{ img: "https://example.com/image.png", label: "Image Label", pos: "t", w: 60, h: 60, constraint: "off" }
flowchart TD
A@{ img: "https://example.com/image.png", label: "Image Label", pos: "t", w: 60, h: 60, constraint: "off" }
Parameters
- img: The URL of the image to be displayed.
- label: The text label associated with the image. This can be any string. If not defined, no label will be displayed.
- pos: The position of the label. If not defined, the label will default to the bottom of the image. Possible values are:
t
b
- w: The width of the image. If not defined, this will default to the natural width of the image.
- h: The height of the image. If not defined, this will default to the natural height of the image.
- constraint: Determines if the image should constrain the node size. This setting also ensures the image maintains its original aspect ratio, adjusting the height (
h
) accordingly to the width (w
). If not defined, this will default tooff
Possible values are:on
off
These new shapes provide additional flexibility and visual appeal to your flowcharts, making them more informative and engaging.
Links between nodes
Nodes can be connected with links/edges. It is possible to have different types of links or attach a text string to a link.
A link with arrow head
flowchart LR
A-->B
flowchart LR
A-->B
An open link
flowchart LR
A --- B
flowchart LR
A --- B
Text on links
flowchart LR
A-- This is the text! ---B
flowchart LR
A-- This is the text! ---B
or
flowchart LR
A---|This is the text|B
flowchart LR
A---|This is the text|B
A link with arrow head and text
flowchart LR
A-->|text|B
flowchart LR
A-->|text|B
or
flowchart LR
A-- text -->B
flowchart LR
A-- text -->B
Dotted link
flowchart LR
A-.->B;
flowchart LR
A-.->B;
Dotted link with text
flowchart LR
A-. text .-> B
flowchart LR
A-. text .-> B
Thick link
flowchart LR
A ==> B
flowchart LR
A ==> B
Thick link with text
flowchart LR
A == text ==> B
flowchart LR
A == text ==> B
An invisible link
This can be a useful tool in some instances where you want to alter the default positioning of a node.
flowchart LR
A ~~~ B
flowchart LR
A ~~~ B
Chaining of links
It is possible declare many links in the same line as per below:
flowchart LR
A -- text --> B -- text2 --> C
flowchart LR
A -- text --> B -- text2 --> C
It is also possible to declare multiple nodes links in the same line as per below:
flowchart LR
a --> b & c--> d
flowchart LR
a --> b & c--> d
You can then describe dependencies in a very expressive way. Like the one-liner below:
flowchart TB
A & B--> C & D
flowchart TB
A & B--> C & D
If you describe the same diagram using the basic syntax, it will take four lines. A
word of warning, one could go overboard with this making the flowchart harder to read in
markdown form. The Swedish word lagom
comes to mind. It means, not too much and not too little.
This goes for expressive syntaxes as well.
flowchart TB
A --> C
A --> D
B --> C
B --> D
flowchart TB
A --> C
A --> D
B --> C
B --> D
Attaching an ID to Edges
Mermaid now supports assigning IDs to edges, similar to how IDs and metadata can be attached to nodes. This feature lays the groundwork for more advanced styling, classes, and animation capabilities on edges.
Syntax:
To give an edge an ID, prepend the edge syntax with the ID followed by an @
character. For example:
flowchart LR
A e1@–> B
flowchart LR
A e1@–> B
In this example, e1
is the ID of the edge connecting A
to B
. You can then use this ID in later definitions or style statements, just like with nodes.
Turning an Animation On
Once you have assigned an ID to an edge, you can turn on animations for that edge by defining the edge’s properties:
flowchart LR
A e1@==> B
e1@{ animate: true }
flowchart LR
A e1@==> B
e1@{ animate: true }
This tells Mermaid that the edge e1
should be animated.
Selecting Type of Animation
In the initial version, two animation speeds are supported: fast
and slow
. Selecting a specific animation type is a shorthand for enabling animation and setting the animation speed in one go.
Examples:
flowchart LR
A e1@–> B
e1@{ animation: fast }
flowchart LR
A e1@–> B
e1@{ animation: fast }
This is equivalent to { animate: true, animation: fast }
.
Using classDef Statements for Animations
You can also animate edges by assigning a class to them and then defining animation properties in a classDef
statement. For example:
flowchart LR
A e1@–> B
classDef animate stroke-dasharray: 9,5,stroke-dashoffset: 900,animation: dash 25s linear infinite;
class e1 animate
flowchart LR
A e1@–> B
classDef animate stroke-dasharray: 9,5,stroke-dashoffset: 900,animation: dash 25s linear infinite;
class e1 animate
In this snippet:
e1@-->
creates an edge with IDe1
.classDef animate
defines a class namedanimate
with styling and animation properties.class e1 animate
applies theanimate
class to the edgee1
.
Note on Escaping Commas:
When setting the stroke-dasharray
property, remember to escape commas as \,
since commas are used as delimiters in Mermaid’s style definitions.
New arrow types
There are new types of arrows supported:
- circle edge
- cross edge
Circle edge example
flowchart LR
A --o B
flowchart LR
A --o B
Cross edge example
flowchart LR
A --x B
flowchart LR
A --x B
Multi directional arrows
There is the possibility to use multidirectional arrows.
flowchart LR
A o--o B
B <--> C
C x--x D
flowchart LR
A o--o B
B <--> C
C x--x D
Minimum length of a link
Each node in the flowchart is ultimately assigned to a rank in the rendered graph, i.e. to a vertical or horizontal level (depending on the flowchart orientation), based on the nodes to which it is linked. By default, links can span any number of ranks, but you can ask for any link to be longer than the others by adding extra dashes in the link definition.
In the following example, two extra dashes are added in the link from node B to node E, so that it spans two more ranks than regular links:
flowchart TD
A[Start] --> B{Is it?}
B -->|Yes| C[OK]
C --> D[Rethink]
D --> B
B ---->|No| E[End]
flowchart TD
A[Start] --> B{Is it?}
B -->|Yes| C[OK]
C --> D[Rethink]
D --> B
B ---->|No| E[End]
Note
Links may still be made longer than the requested number of ranks by the rendering engine to accommodate other requests.
When the link label is written in the middle of the link, the extra dashes must be added on the right side of the link. The following example is equivalent to the previous one:
flowchart TD
A[Start] --> B{Is it?}
B -- Yes --> C[OK]
C --> D[Rethink]
D --> B
B -- No ----> E[End]
flowchart TD
A[Start] --> B{Is it?}
B -- Yes --> C[OK]
C --> D[Rethink]
D --> B
B -- No ----> E[End]
For dotted or thick links, the characters to add are equals signs or dots, as summed up in the following table:
Length | 1 | 2 | 3 |
---|---|---|---|
Normal | --- |
---- |
----- |
Normal with arrow | --> |
---> |
----> |
Thick | === |
==== |
===== |
Thick with arrow | ==> |
===> |
====> |
Dotted | -.- |
-..- |
-...- |
Dotted with arrow | -.-> |
-..-> |
-...-> |
Special characters that break syntax
It is possible to put text within quotes in order to render more troublesome characters. As in the example below:
flowchart LR
id1["This is the (text) in the box"]
flowchart LR
id1["This is the (text) in the box"]
Entity codes to escape characters
It is possible to escape characters using the syntax exemplified here.
flowchart LR
A["A double quote:#quot;"] --> B["A dec char:#9829;"]
flowchart LR
A["A double quote:#quot;"] --> B["A dec char:#9829;"]
Numbers given are base 10, so #
can be encoded as #35;
. It is also supported to use HTML character names.
Subgraphs
subgraph title
graph definition
end
An example below:
flowchart TB
c1-->a2
subgraph one
a1-->a2
end
subgraph two
b1-->b2
end
subgraph three
c1-->c2
end
flowchart TB
c1-->a2
subgraph one
a1-->a2
end
subgraph two
b1-->b2
end
subgraph three
c1-->c2
end
You can also set an explicit id for the subgraph.
flowchart TB
c1-->a2
subgraph ide1 [one]
a1-->a2
end
flowchart TB
c1-->a2
subgraph ide1 [one]
a1-->a2
end
flowcharts
With the graphtype flowchart it is also possible to set edges to and from subgraphs as in the flowchart below.
flowchart TB
c1-->a2
subgraph one
a1-->a2
end
subgraph two
b1-->b2
end
subgraph three
c1-->c2
end
one --> two
three --> two
two --> c2
flowchart TB
c1-->a2
subgraph one
a1-->a2
end
subgraph two
b1-->b2
end
subgraph three
c1-->c2
end
one --> two
three --> two
two --> c2
Direction in subgraphs
With the graphtype flowcharts you can use the direction statement to set the direction which the subgraph will render like in this example.
flowchart LR
subgraph TOP
direction TB
subgraph B1
direction RL
i1 -->f1
end
subgraph B2
direction BT
i2 -->f2
end
end
A --> TOP --> B
B1 --> B2
flowchart LR
subgraph TOP
direction TB
subgraph B1
direction RL
i1 -->f1
end
subgraph B2
direction BT
i2 -->f2
end
end
A --> TOP --> B
B1 --> B2
Limitation
If any of a subgraph's nodes are linked to the outside, subgraph direction will be ignored. Instead the subgraph will inherit the direction of the parent graph:
flowchart LR
subgraph subgraph1
direction TB
top1[top] --> bottom1[bottom]
end
subgraph subgraph2
direction TB
top2[top] --> bottom2[bottom]
end
%% ^ These subgraphs are identical, except for the links to them:
%% Link *to* subgraph1: subgraph1 direction is maintained
outside --> subgraph1
%% Link *within* subgraph2:
%% subgraph2 inherits the direction of the top-level graph (LR)
outside ---> top2
flowchart LR
subgraph subgraph1
direction TB
top1[top] --> bottom1[bottom]
end
subgraph subgraph2
direction TB
top2[top] --> bottom2[bottom]
end
%% ^ These subgraphs are identical, except for the links to them:
%% Link *to* subgraph1: subgraph1 direction is maintained
outside --> subgraph1
%% Link *within* subgraph2:
%% subgraph2 inherits the direction of the top-level graph (LR)
outside ---> top2
Markdown Strings
The "Markdown Strings" feature enhances flowcharts and mind maps by offering a more versatile string type, which supports text formatting options such as bold and italics, and automatically wraps text within labels.
%%{init: {"flowchart": {"htmlLabels": false}} }%%
flowchart LR
subgraph "One"
a("`The **cat**
in the hat`") -- "edge label" --> b{{"`The **dog** in the hog`"}}
end
subgraph "`**Two**`"
c("`The **cat**
in the hat`") -- "`Bold **edge label**`" --> d("The dog in the hog")
end
%%{init: {"flowchart": {"htmlLabels": false}} }%%
flowchart LR
subgraph "One"
a("`The **cat**
in the hat`") -- "edge label" --> b{{"`The **dog** in the hog`"}}
end
subgraph "`**Two**`"
c("`The **cat**
in the hat`") -- "`Bold **edge label**`" --> d("The dog in the hog")
end
Formatting:
- For bold text, use double asterisks (
**
) before and after the text. - For italics, use single asterisks (
*
) before and after the text. - With traditional strings, you needed to add
<br>
tags for text to wrap in nodes. However, markdown strings automatically wrap text when it becomes too long and allows you to start a new line by simply using a newline character instead of a<br>
tag.
This feature is applicable to node labels, edge labels, and subgraph labels.
The auto wrapping can be disabled by using
---
config:
markdownAutoWrap: false
---
graph LR
Interaction
It is possible to bind a click event to a node, the click can lead to either a javascript callback or to a link which will be opened in a new browser tab.
Note
This functionality is disabled when using
securityLevel='strict'
and enabled when usingsecurityLevel='loose'
.
click nodeId callback
click nodeId call callback()
- nodeId is the id of the node
- callback is the name of a javascript function defined on the page displaying the graph, the function will be called with the nodeId as parameter.
Examples of tooltip usage below:
<script>
window.callback = function () {
alert('A callback was triggered');
};
</script>
The tooltip text is surrounded in double quotes. The styles of the tooltip are set by the class .mermaidTooltip
.
flowchart LR
A-->B
B-->C
C-->D
click A callback "Tooltip for a callback"
click B "https://www.github.com" "This is a tooltip for a link"
click C call callback() "Tooltip for a callback"
click D href "https://www.github.com" "This is a tooltip for a link"
flowchart LR
A-->B
B-->C
C-->D
click A callback "Tooltip for a callback"
click B "https://www.github.com" "This is a tooltip for a link"
click C call callback() "Tooltip for a callback"
click D href "https://www.github.com" "This is a tooltip for a link"
Success The tooltip functionality and the ability to link to urls are available from version 0.5.2.
?> Due to limitations with how Docsify handles JavaScript callback functions, an alternate working demo for the above code can be viewed at this jsfiddle.
Links are opened in the same browser tab/window by default. It is possible to change this by adding a link target to the click definition (_self
, _blank
, _parent
and _top
are supported):
flowchart LR
A-->B
B-->C
C-->D
D-->E
click A "https://www.github.com" _blank
click B "https://www.github.com" "Open this in a new tab" _blank
click C href "https://www.github.com" _blank
click D href "https://www.github.com" "Open this in a new tab" _blank
flowchart LR
A-->B
B-->C
C-->D
D-->E
click A "https://www.github.com" _blank
click B "https://www.github.com" "Open this in a new tab" _blank
click C href "https://www.github.com" _blank
click D href "https://www.github.com" "Open this in a new tab" _blank
Beginner's tip—a full example using interactive links in a html context:
<body>
<pre class="mermaid">
flowchart LR
A-->B
B-->C
C-->D
click A callback "Tooltip"
click B "https://www.github.com" "This is a link"
click C call callback() "Tooltip"
click D href "https://www.github.com" "This is a link"
</pre>
<script>
window.callback = function () {
alert('A callback was triggered');
};
const config = {
startOnLoad: true,
flowchart: { useMaxWidth: true, htmlLabels: true, curve: 'cardinal' },
securityLevel: 'loose',
};
mermaid.initialize(config);
</script>
</body>
Comments
Comments can be entered within a flow diagram, which will be ignored by the parser. Comments need to be on their own line, and must be prefaced with %%
(double percent signs). Any text after the start of the comment to the next newline will be treated as a comment, including any flow syntax
flowchart LR
%% this is a comment A -- text --> B{node}
A -- text --> B -- text2 --> C
flowchart LR
%% this is a comment A -- text --> B{node}
A -- text --> B -- text2 --> C
Styling and classes
Styling links
It is possible to style links. For instance, you might want to style a link that is going backwards in the flow. As links have no ids in the same way as nodes, some other way of deciding what style the links should be attached to is required. Instead of ids, the order number of when the link was defined in the graph is used, or use default to apply to all links. In the example below the style defined in the linkStyle statement will belong to the fourth link in the graph:
linkStyle 3 stroke:#ff3,stroke-width:4px,color:red;
It is also possible to add style to multiple links in a single statement, by separating link numbers with commas:
linkStyle 1,2,7 color:blue;
Styling line curves
It is possible to style the type of curve used for lines between items, if the default method does not meet your needs.
Available curve styles include basis
, bumpX
, bumpY
, cardinal
, catmullRom
, linear
, monotoneX
, monotoneY
,
natural
, step
, stepAfter
, and stepBefore
.
In this example, a left-to-right graph uses the stepBefore
curve style:
%%{ init: { 'flowchart': { 'curve': 'stepBefore' } } }%%
graph LR
For a full list of available curves, including an explanation of custom curves, refer to the Shapes documentation in the d3-shape project.
Styling a node
It is possible to apply specific styles such as a thicker border or a different background color to a node.
flowchart LR
id1(Start)-->id2(Stop)
style id1 fill:#f9f,stroke:#333,stroke-width:4px
style id2 fill:#bbf,stroke:#f66,stroke-width:2px,color:#fff,stroke-dasharray: 5 5
flowchart LR
id1(Start)-->id2(Stop)
style id1 fill:#f9f,stroke:#333,stroke-width:4px
style id2 fill:#bbf,stroke:#f66,stroke-width:2px,color:#fff,stroke-dasharray: 5 5
Classes
More convenient than defining the style every time is to define a class of styles and attach this class to the nodes that should have a different look.
A class definition looks like the example below:
classDef className fill:#f9f,stroke:#333,stroke-width:4px;
Also, it is possible to define style to multiple classes in one statement:
classDef firstClassName,secondClassName font-size:12pt;
Attachment of a class to a node is done as per below:
class nodeId1 className;
It is also possible to attach a class to a list of nodes in one statement:
class nodeId1,nodeId2 className;
A shorter form of adding a class is to attach the classname to the node using the :::
operator as per below:
flowchart LR
A:::someclass --> B
classDef someclass fill:#f96
flowchart LR
A:::someclass --> B
classDef someclass fill:#f96
This form can be used when declaring multiple links between nodes:
flowchart LR
A:::foo & B:::bar --> C:::foobar
classDef foo stroke:#f00
classDef bar stroke:#0f0
classDef foobar stroke:#00f
flowchart LR
A:::foo & B:::bar --> C:::foobar
classDef foo stroke:#f00
classDef bar stroke:#0f0
classDef foobar stroke:#00f
CSS classes
It is also possible to predefine classes in CSS styles that can be applied from the graph definition as in the example below:
Example style
<style>
.cssClass > rect {
fill: #ff0000;
stroke: #ffff00;
stroke-width: 4px;
}
</style>
Example definition
flowchart LR
A-->B[AAA<span>BBB</span>]
B-->D
class A cssClass
flowchart LR
A-->B[AAA<span>BBB</span>]
B-->D
class A cssClass
Default class
If a class is named default it will be assigned to all classes without specific class definitions.
classDef default fill:#f9f,stroke:#333,stroke-width:4px;
Basic support for fontawesome
It is possible to add icons from fontawesome.
The icons are accessed via the syntax fa:#icon class name#.
flowchart TD
B["fa:fa-twitter for peace"]
B-->C[fa:fa-ban forbidden]
B-->D(fa:fa-spinner)
B-->E(A fa:fa-camera-retro perhaps?)
flowchart TD
B["fa:fa-twitter for peace"]
B-->C[fa:fa-ban forbidden]
B-->D(fa:fa-spinner)
B-->E(A fa:fa-camera-retro perhaps?)
Mermaid supports Font Awesome if the CSS is included on the website. Mermaid does not have any restriction on the version of Font Awesome that can be used.
Please refer the Official Font Awesome Documentation on how to include it in your website.
Adding this snippet in the <head>
would add support for Font Awesome v6.5.1
<link
href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css"
rel="stylesheet"
/>
Custom icons
It is possible to use custom icons served from Font Awesome as long as the website imports the corresponding kit.
Note that this is currently a paid feature from Font Awesome.
For custom icons, you need to use the fak
prefix.
Example
flowchart TD
B[fa:fa-twitter] %% standard icon
B-->E(fak:fa-custom-icon-name) %% custom icon
And trying to render it
flowchart TD
B["fa:fa-twitter for peace"]
B-->C["fab:fa-truck-bold a custom icon"]
flowchart TD
B["fa:fa-twitter for peace"]
B-->C["fab:fa-truck-bold a custom icon"]
Graph declarations with spaces between vertices and link and without semicolon
-
In graph declarations, the statements also can now end without a semicolon. After release 0.2.16, ending a graph statement with semicolon is just optional. So the below graph declaration is also valid along with the old declarations of the graph.
-
A single space is allowed between vertices and the link. However there should not be any space between a vertex and its text and a link and its text. The old syntax of graph declaration will also work and hence this new feature is optional and is introduced to improve readability.
Below is the new declaration of the graph edges which is also valid along with the old declaration of the graph edges.
flowchart LR
A[Hard edge] -->|Link text| B(Round edge)
B --> C{Decision}
C -->|One| D[Result one]
C -->|Two| E[Result two]
flowchart LR
A[Hard edge] -->|Link text| B(Round edge)
B --> C{Decision}
C -->|One| D[Result one]
C -->|Two| E[Result two]
Configuration
Renderer
The layout of the diagram is done with the renderer. The default renderer is dagre.
Starting with Mermaid version 9.4, you can use an alternate renderer named elk. The elk renderer is better for larger and/or more complex diagrams.
The elk renderer is an experimental feature. You can change the renderer to elk by adding this directive:
%%{init: {"flowchart": {"defaultRenderer": "elk"}} }%%
Note
Note that the site needs to use mermaid version 9.4+ for this to work and have this featured enabled in the lazy-loading configuration.
Width
It is possible to adjust the width of the rendered flowchart.
This is done by defining mermaid.flowchartConfig or by the CLI to use a JSON file with the configuration. How to use the CLI is described in the mermaidCLI page. mermaid.flowchartConfig can be set to a JSON string with config parameters or the corresponding object.
mermaid.flowchartConfig = {
width: 100%
}