> **Warning**
>
> ## THIS IS AN AUTOGENERATED FILE. DO NOT EDIT.
>
> ## Please edit the corresponding file in [/packages/mermaid/src/docs/syntax/sequenceDiagram.md](../../packages/mermaid/src/docs/syntax/sequenceDiagram.md).
# Sequence diagrams
> A Sequence diagram is an interaction diagram that shows how processes operate with one another and in what order.
Mermaid can render sequence diagrams.
```mermaid-example
sequenceDiagram
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
```mermaid
sequenceDiagram
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
> **Note**
> A note on nodes, the word "end" could potentially break the diagram, due to the way that the mermaid language is scripted.
>
> If unavoidable, one must use parentheses(), quotation marks "", or brackets {},\[], to enclose the word "end". i.e : (end), \[end], {end}.
## Syntax
### Participants
The participants can be defined implicitly as in the first example on this page. The participants or actors are
rendered in order of appearance in the diagram source text. Sometimes you might want to show the participants in a
different order than how they appear in the first message. It is possible to specify the actor's order of
appearance by doing the following:
```mermaid-example
sequenceDiagram
participant Alice
participant Bob
Alice->>Bob: Hi Bob
Bob->>Alice: Hi Alice
```
```mermaid
sequenceDiagram
participant Alice
participant Bob
Alice->>Bob: Hi Bob
Bob->>Alice: Hi Alice
```
### Actors
If you specifically want to use the actor symbol instead of a rectangle with text you can do so by using actor statements as per below.
```mermaid-example
sequenceDiagram
actor Alice
actor Bob
Alice->>Bob: Hi Bob
Bob->>Alice: Hi Alice
```
```mermaid
sequenceDiagram
actor Alice
actor Bob
Alice->>Bob: Hi Bob
Bob->>Alice: Hi Alice
```
### Aliases
The actor can have a convenient identifier and a descriptive label.
```mermaid-example
sequenceDiagram
participant A as Alice
participant J as John
A->>J: Hello John, how are you?
J->>A: Great!
```
```mermaid
sequenceDiagram
participant A as Alice
participant J as John
A->>J: Hello John, how are you?
J->>A: Great!
```
### Actor Creation and Destruction (v10.3.0+)
It is possible to create and destroy actors by messages. To do so, add a create or destroy directive before the message.
create participant B
A --> B: Hello
Create directives support actor/participant distinction and aliases. The sender or the recipient of a message can be destroyed but only the recipient can be created.
```mermaid-example
sequenceDiagram
Alice->>Bob: Hello Bob, how are you ?
Bob->>Alice: Fine, thank you. And you?
create participant Carl
Alice->>Carl: Hi Carl!
create actor D as Donald
Carl->>D: Hi!
destroy Carl
Alice-xCarl: We are too many
destroy Bob
Bob->>Alice: I agree
```
```mermaid
sequenceDiagram
Alice->>Bob: Hello Bob, how are you ?
Bob->>Alice: Fine, thank you. And you?
create participant Carl
Alice->>Carl: Hi Carl!
create actor D as Donald
Carl->>D: Hi!
destroy Carl
Alice-xCarl: We are too many
destroy Bob
Bob->>Alice: I agree
```
#### Unfixable actor/participant creation/deletion error
If an error of the following type occurs when creating or deleting an actor/participant:
> The destroyed participant **participant-name** does not have an associated destroying message after its declaration. Please check the sequence diagram.
And fixing diagram code does not get rid of this error and rendering of all other diagrams results in the same error, then you need to update the mermaid version to (v10.7.0+).
### Grouping / Box
The actor(s) can be grouped in vertical boxes. You can define a color (if not, it will be transparent) and/or a descriptive label using the following notation:
box Aqua Group Description
... actors ...
end
box Group without description
... actors ...
end
box rgb(33,66,99)
... actors ...
end
> **Note**
> If your group name is a color you can force the color to be transparent:
box transparent Aqua
... actors ...
end
```mermaid-example
sequenceDiagram
box Purple Alice & John
participant A
participant J
end
box Another Group
participant B
participant C
end
A->>J: Hello John, how are you?
J->>A: Great!
A->>B: Hello Bob, how is Charly?
B->>C: Hello Charly, how are you?
```
```mermaid
sequenceDiagram
box Purple Alice & John
participant A
participant J
end
box Another Group
participant B
participant C
end
A->>J: Hello John, how are you?
J->>A: Great!
A->>B: Hello Bob, how is Charly?
B->>C: Hello Charly, how are you?
```
## Messages
Messages can be of two displayed either solid or with a dotted line.
[Actor][Arrow][Actor]:Message text
There are six types of arrows currently supported:
| Type | Description |
| ------ | ------------------------------------------------ |
| `->` | Solid line without arrow |
| `-->` | Dotted line without arrow |
| `->>` | Solid line with arrowhead |
| `-->>` | Dotted line with arrowhead |
| `-x` | Solid line with a cross at the end |
| `--x` | Dotted line with a cross at the end. |
| `-)` | Solid line with an open arrow at the end (async) |
| `--)` | Dotted line with a open arrow at the end (async) |
## Activations
It is possible to activate and deactivate an actor. (de)activation can be dedicated declarations:
```mermaid-example
sequenceDiagram
Alice->>John: Hello John, how are you?
activate John
John-->>Alice: Great!
deactivate John
```
```mermaid
sequenceDiagram
Alice->>John: Hello John, how are you?
activate John
John-->>Alice: Great!
deactivate John
```
There is also a shortcut notation by appending `+`/`-` suffix to the message arrow:
```mermaid-example
sequenceDiagram
Alice->>+John: Hello John, how are you?
John-->>-Alice: Great!
```
```mermaid
sequenceDiagram
Alice->>+John: Hello John, how are you?
John-->>-Alice: Great!
```
Activations can be stacked for same actor:
```mermaid-example
sequenceDiagram
Alice->>+John: Hello John, how are you?
Alice->>+John: John, can you hear me?
John-->>-Alice: Hi Alice, I can hear you!
John-->>-Alice: I feel great!
```
```mermaid
sequenceDiagram
Alice->>+John: Hello John, how are you?
Alice->>+John: John, can you hear me?
John-->>-Alice: Hi Alice, I can hear you!
John-->>-Alice: I feel great!
```
## Notes
It is possible to add notes to a sequence diagram. This is done by the notation
Note \[ right of | left of | over ] \[Actor]: Text in note content
See the example below:
```mermaid-example
sequenceDiagram
participant John
Note right of John: Text in note
```
```mermaid
sequenceDiagram
participant John
Note right of John: Text in note
```
It is also possible to create notes spanning two participants:
```mermaid-example
sequenceDiagram
Alice->John: Hello John, how are you?
Note over Alice,John: A typical interaction
```
```mermaid
sequenceDiagram
Alice->John: Hello John, how are you?
Note over Alice,John: A typical interaction
```
It is also possible to add a line break (applies to text input in general):
```mermaid-example
sequenceDiagram
Alice->John: Hello John, how are you?
Note over Alice,John: A typical interaction
But now in two lines
```
```mermaid
sequenceDiagram
Alice->John: Hello John, how are you?
Note over Alice,John: A typical interaction
But now in two lines
```
## Loops
It is possible to express loops in a sequence diagram. This is done by the notation
loop Loop text
... statements ...
end
See the example below:
```mermaid-example
sequenceDiagram
Alice->John: Hello John, how are you?
loop Every minute
John-->Alice: Great!
end
```
```mermaid
sequenceDiagram
Alice->John: Hello John, how are you?
loop Every minute
John-->Alice: Great!
end
```
## Alt
It is possible to express alternative paths in a sequence diagram. This is done by the notation
alt Describing text
... statements ...
else
... statements ...
end
or if there is sequence that is optional (if without else).
opt Describing text
... statements ...
end
See the example below:
```mermaid-example
sequenceDiagram
Alice->>Bob: Hello Bob, how are you?
alt is sick
Bob->>Alice: Not so good :(
else is well
Bob->>Alice: Feeling fresh like a daisy
end
opt Extra response
Bob->>Alice: Thanks for asking
end
```
```mermaid
sequenceDiagram
Alice->>Bob: Hello Bob, how are you?
alt is sick
Bob->>Alice: Not so good :(
else is well
Bob->>Alice: Feeling fresh like a daisy
end
opt Extra response
Bob->>Alice: Thanks for asking
end
```
## Parallel
It is possible to show actions that are happening in parallel.
This is done by the notation
par [Action 1]
... statements ...
and [Action 2]
... statements ...
and [Action N]
... statements ...
end
See the example below:
```mermaid-example
sequenceDiagram
par Alice to Bob
Alice->>Bob: Hello guys!
and Alice to John
Alice->>John: Hello guys!
end
Bob-->>Alice: Hi Alice!
John-->>Alice: Hi Alice!
```
```mermaid
sequenceDiagram
par Alice to Bob
Alice->>Bob: Hello guys!
and Alice to John
Alice->>John: Hello guys!
end
Bob-->>Alice: Hi Alice!
John-->>Alice: Hi Alice!
```
It is also possible to nest parallel blocks.
```mermaid-example
sequenceDiagram
par Alice to Bob
Alice->>Bob: Go help John
and Alice to John
Alice->>John: I want this done today
par John to Charlie
John->>Charlie: Can we do this today?
and John to Diana
John->>Diana: Can you help us today?
end
end
```
```mermaid
sequenceDiagram
par Alice to Bob
Alice->>Bob: Go help John
and Alice to John
Alice->>John: I want this done today
par John to Charlie
John->>Charlie: Can we do this today?
and John to Diana
John->>Diana: Can you help us today?
end
end
```
## Critical Region
It is possible to show actions that must happen automatically with conditional handling of circumstances.
This is done by the notation
critical [Action that must be performed]
... statements ...
option [Circumstance A]
... statements ...
option [Circumstance B]
... statements ...
end
See the example below:
```mermaid-example
sequenceDiagram
critical Establish a connection to the DB
Service-->DB: connect
option Network timeout
Service-->Service: Log error
option Credentials rejected
Service-->Service: Log different error
end
```
```mermaid
sequenceDiagram
critical Establish a connection to the DB
Service-->DB: connect
option Network timeout
Service-->Service: Log error
option Credentials rejected
Service-->Service: Log different error
end
```
It is also possible to have no options at all
```mermaid-example
sequenceDiagram
critical Establish a connection to the DB
Service-->DB: connect
end
```
```mermaid
sequenceDiagram
critical Establish a connection to the DB
Service-->DB: connect
end
```
This critical block can also be nested, equivalently to the `par` statement as seen above.
## Break
It is possible to indicate a stop of the sequence within the flow (usually used to model exceptions).
This is done by the notation
break [something happened]
... statements ...
end
See the example below:
```mermaid-example
sequenceDiagram
Consumer-->API: Book something
API-->BookingService: Start booking process
break when the booking process fails
API-->Consumer: show failure
end
API-->BillingService: Start billing process
```
```mermaid
sequenceDiagram
Consumer-->API: Book something
API-->BookingService: Start booking process
break when the booking process fails
API-->Consumer: show failure
end
API-->BillingService: Start billing process
```
## Background Highlighting
It is possible to highlight flows by providing colored background rects. This is done by the notation
The colors are defined using rgb and rgba syntax.
rect rgb(0, 255, 0)
... content ...
end
rect rgba(0, 0, 255, .1)
... content ...
end
See the examples below:
```mermaid-example
sequenceDiagram
participant Alice
participant John
rect rgb(191, 223, 255)
note right of Alice: Alice calls John.
Alice->>+John: Hello John, how are you?
rect rgb(200, 150, 255)
Alice->>+John: John, can you hear me?
John-->>-Alice: Hi Alice, I can hear you!
end
John-->>-Alice: I feel great!
end
Alice ->>+ John: Did you want to go to the game tonight?
John -->>- Alice: Yeah! See you there.
```
```mermaid
sequenceDiagram
participant Alice
participant John
rect rgb(191, 223, 255)
note right of Alice: Alice calls John.
Alice->>+John: Hello John, how are you?
rect rgb(200, 150, 255)
Alice->>+John: John, can you hear me?
John-->>-Alice: Hi Alice, I can hear you!
end
John-->>-Alice: I feel great!
end
Alice ->>+ John: Did you want to go to the game tonight?
John -->>- Alice: Yeah! See you there.
```
## Comments
Comments can be entered within a sequence 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 diagram syntax
```mermaid-example
sequenceDiagram
Alice->>John: Hello John, how are you?
%% this is a comment
John-->>Alice: Great!
```
```mermaid
sequenceDiagram
Alice->>John: Hello John, how are you?
%% this is a comment
John-->>Alice: Great!
```
## Entity codes to escape characters
It is possible to escape characters using the syntax exemplified here.
```mermaid-example
sequenceDiagram
A->>B: I #9829; you!
B->>A: I #9829; you #infin; times more!
```
```mermaid
sequenceDiagram
A->>B: I #9829; you!
B->>A: I #9829; you #infin; times more!
```
Numbers given are base 10, so `#` can be encoded as `#35;`. It is also supported to use HTML character names.
Because semicolons can be used instead of line breaks to define the markup, you need to use `#59;` to include a semicolon in message text.
## sequenceNumbers
It is possible to get a sequence number attached to each arrow in a sequence diagram. This can be configured when adding mermaid to the website as shown below:
```html
```
It can also be turned on via the diagram code as in the diagram:
```mermaid-example
sequenceDiagram
autonumber
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!
```
```mermaid
sequenceDiagram
autonumber
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!
```
## Actor Menus
Actors can have popup-menus containing individualized links to external pages. For example, if an actor represented a web service, useful links might include a link to the service health dashboard, repo containing the code for the service, or a wiki page describing the service.
This can be configured by adding one or more link lines with the format:
link : @
```mermaid-example
sequenceDiagram
participant Alice
participant John
link Alice: Dashboard @ https://dashboard.contoso.com/alice
link Alice: Wiki @ https://wiki.contoso.com/alice
link John: Dashboard @ https://dashboard.contoso.com/john
link John: Wiki @ https://wiki.contoso.com/john
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
```mermaid
sequenceDiagram
participant Alice
participant John
link Alice: Dashboard @ https://dashboard.contoso.com/alice
link Alice: Wiki @ https://wiki.contoso.com/alice
link John: Dashboard @ https://dashboard.contoso.com/john
link John: Wiki @ https://wiki.contoso.com/john
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
#### Advanced Menu Syntax
There is an advanced syntax that relies on JSON formatting. If you are comfortable with JSON format, then this exists as well.
This can be configured by adding the links lines with the format:
links :
An example is below:
```mermaid-example
sequenceDiagram
participant Alice
participant John
links Alice: {"Dashboard": "https://dashboard.contoso.com/alice", "Wiki": "https://wiki.contoso.com/alice"}
links John: {"Dashboard": "https://dashboard.contoso.com/john", "Wiki": "https://wiki.contoso.com/john"}
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
```mermaid
sequenceDiagram
participant Alice
participant John
links Alice: {"Dashboard": "https://dashboard.contoso.com/alice", "Wiki": "https://wiki.contoso.com/alice"}
links John: {"Dashboard": "https://dashboard.contoso.com/john", "Wiki": "https://wiki.contoso.com/john"}
Alice->>John: Hello John, how are you?
John-->>Alice: Great!
Alice-)John: See you later!
```
## Styling
Styling of a sequence diagram is done by defining a number of css classes. During rendering these classes are extracted from the file located at src/themes/sequence.scss
### Classes used
| Class | Description |
| ------------ | ----------------------------------------------------------- |
| actor | Style for the actor box at the top of the diagram. |
| text.actor | Styles for text in the actor box at the top of the diagram. |
| actor-line | The vertical line for an actor. |
| messageLine0 | Styles for the solid message line. |
| messageLine1 | Styles for the dotted message line. |
| messageText | Defines styles for the text on the message arrows. |
| labelBox | Defines styles label to left in a loop. |
| labelText | Styles for the text in label for loops. |
| loopText | Styles for the text in the loop box. |
| loopLine | Defines styles for the lines in the loop box. |
| note | Styles for the note box. |
| noteText | Styles for the text on in the note boxes. |
### Sample stylesheet
```css
body {
background: white;
}
.actor {
stroke: #ccccff;
fill: #ececff;
}
text.actor {
fill: black;
stroke: none;
font-family: Helvetica;
}
.actor-line {
stroke: grey;
}
.messageLine0 {
stroke-width: 1.5;
stroke-dasharray: '2 2';
marker-end: 'url(#arrowhead)';
stroke: black;
}
.messageLine1 {
stroke-width: 1.5;
stroke-dasharray: '2 2';
stroke: black;
}
#arrowhead {
fill: black;
}
.messageText {
fill: black;
stroke: none;
font-family: 'trebuchet ms', verdana, arial;
font-size: 14px;
}
.labelBox {
stroke: #ccccff;
fill: #ececff;
}
.labelText {
fill: black;
stroke: none;
font-family: 'trebuchet ms', verdana, arial;
}
.loopText {
fill: black;
stroke: none;
font-family: 'trebuchet ms', verdana, arial;
}
.loopLine {
stroke-width: 2;
stroke-dasharray: '2 2';
marker-end: 'url(#arrowhead)';
stroke: #ccccff;
}
.note {
stroke: #decc93;
fill: #fff5ad;
}
.noteText {
fill: black;
stroke: none;
font-family: 'trebuchet ms', verdana, arial;
font-size: 14px;
}
```
## Configuration
It is possible to adjust the margins for rendering the sequence diagram.
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](../config/mermaidCLI.md) page.
`mermaid.sequenceConfig` can be set to a JSON string with config parameters or the corresponding object.
```javascript
mermaid.sequenceConfig = {
diagramMarginX: 50,
diagramMarginY: 10,
boxTextMargin: 5,
noteMargin: 10,
messageMargin: 35,
mirrorActors: true,
};
```
### Possible configuration parameters:
| Parameter | Description | Default value |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------ |
| mirrorActors | Turns on/off the rendering of actors below the diagram as well as above it | false |
| bottomMarginAdj | Adjusts how far down the graph ended. Wide borders styles with css could generate unwanted clipping which is why this config param exists. | 1 |
| actorFontSize | Sets the font size for the actor's description | 14 |
| actorFontFamily | Sets the font family for the actor's description | "Open Sans", sans-serif |
| actorFontWeight | Sets the font weight for the actor's description | "Open Sans", sans-serif |
| noteFontSize | Sets the font size for actor-attached notes | 14 |
| noteFontFamily | Sets the font family for actor-attached notes | "trebuchet ms", verdana, arial |
| noteFontWeight | Sets the font weight for actor-attached notes | "trebuchet ms", verdana, arial |
| noteAlign | Sets the text alignment for text in actor-attached notes | center |
| messageFontSize | Sets the font size for actor<->actor messages | 16 |
| messageFontFamily | Sets the font family for actor<->actor messages | "trebuchet ms", verdana, arial |
| messageFontWeight | Sets the font weight for actor<->actor messages | "trebuchet ms", verdana, arial |