The sequence -> is used to draw a message between two participants. Participants do not have to be explicitly declared. To have a dotted arrow, you use --> It is also possible to use <- and <--. That does not change the drawing, but may improve readability. Note that this is only true for sequence diagrams, rules are different for the other diagrams.
@startuml
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response
Alice -> Bob: Another authentication Request
Alice <-- Bob: Another authentication Response
@enduml
Declaring participant
If the keyword participant is used to declare a participant, more control on that participant is possible. The order of declaration will be the (default) order of display. Using these other keywords to declare participants will change the shape of the participant representation:
actor
boundary
control
entity
database
collections
queue
@startuml
participant participant as Foo
actor actor as Foo1
boundary boundary as Foo2
control control as Foo3
entity entity as Foo4
database database as Foo5
collections collections as Foo6
queue queue as Foo7
Foo -> Foo1 : To actor
Foo -> Foo2 : To boundary
Foo -> Foo3 : To control
Foo -> Foo4 : To entity
Foo -> Foo5 : To database
Foo -> Foo6 : To collections
Foo -> Foo7: To queue
@enduml
Rename a participant using the as keyword. You can also change the background color of actor or participant.
@startuml
actor Bob #red
' The only difference between actor
'and participant is the drawing
participant Alice
participant "I have a really\nlong name" as L #99FF99
/' You can also declare:
participant L as "I have a really\nlong name" #99FF99
'/
Alice->Bob: Authentication Request
Bob->Alice: Authentication Response
Bob->L: Log transaction
@enduml
You can use the order keyword to customize the display order of participants.
@startuml
participant Last order 30
participant Middle order 20
participant First order 10
@enduml
Use non-letters in participants
You can use quotes to define participants. And you can use the as keyword to give an alias to those participants.
@startuml
Alice -> "Bob()" : Hello
"Bob()" -> "This is very\nlong" as Long
' You can also declare:
' "Bob()" -> Long as "This is very\nlong"
Long --> "Bob()" : ok
@enduml
Message to Self
A participant can send a message to itself. It is also possible to have multi-line using \n.
@startuml
Alice->Alice: This is a signal to self.\nIt also demonstrates\nmultiline \ntext
@enduml
Text alignment
Text alignment on arrows can be set to left, right or center using skinparam sequenceMessageAlign. You can also use direction or reverseDirection to align text depending on arrow direction. Further details and examples of this are available on the skinparam page.
@startuml
skinparam sequenceMessageAlign right
Bob -> Alice : Request
Alice -> Bob : Response
@enduml
Text of response message below the arrow
You can put the text of the response message below the arrow, with the skinparam responseMessageBelowArrow true command.
@startuml
skinparam responseMessageBelowArrow true
Bob -> Alice : hello
Alice -> Bob : ok
@enduml
Change arrow style
You can change arrow style by several ways:
add a final x to denote a lost message
use \ or / instead of < or > to have only the bottom or top part of the arrow
repeat the arrow head (for example, >> or //) head to have a thin drawing
use -- instead of - to have a dotted arrow
add a final "o" at arrow head
use bidirectional arrow <->
@startuml
Bob ->x Alice
Bob -> Alice
Bob ->> Alice
Bob -\ Alice
Bob \\- Alice
Bob //-- Alice
Bob ->o Alice
Bob o\\-- Alice
Bob <-> Alice
Bob <->o Alice
@enduml
Change arrow color
You can change the color of individual arrows using the following notation:
@startuml
Bob -[#red]> Alice : hello
Alice -[#0000FF]->Bob : ok
@enduml
Message sequence numbering
The keyword autonumber is used to automatically add an incrementing number to messages.
@startuml
autonumber
Bob -> Alice : Authentication Request
Bob <- Alice : Authentication Response
@enduml
You can specify a startnumber with autonumber //start// , and also an increment with autonumber //start// //increment//.
@startuml
autonumber
Bob -> Alice : Authentication Request
Bob <- Alice : Authentication Response
autonumber 15
Bob -> Alice : Another authentication Request
Bob <- Alice : Another authentication Response
autonumber 40 10
Bob -> Alice : Yet another authentication Request
Bob <- Alice : Yet another authentication Response
@enduml
You can specify a format for your number by using between double-quote. The formatting is done with the Java class DecimalFormat (0 means digit, # means digit and zero if absent). You can use some html tag in the format.
@startuml
autonumber "<b>[000]"
Bob -> Alice : Authentication Request
Bob <- Alice : Authentication Response
autonumber 15 "<b>(<u>##</u>)"
Bob -> Alice : Another authentication Request
Bob <- Alice : Another authentication Response
autonumber 40 10 "<font color=red><b>Message 0 "
Bob -> Alice : Yet another authentication Request
Bob <- Alice : Yet another authentication Response
@enduml
You can also use autonumber stop and autonumber resume //increment// //format// to respectively pause and resume automatic numbering.
@startuml
autonumber 10 10 "<b>[000]"
Bob -> Alice : Authentication Request
Bob <- Alice : Authentication Response
autonumber stop
Bob -> Alice : dummy
autonumber resume "<font color=red><b>Message 0 "
Bob -> Alice : Yet another authentication Request
Bob <- Alice : Yet another authentication Response
autonumber stop
Bob -> Alice : dummy
autonumber resume 1 "<font color=blue><b>Message 0 "
Bob -> Alice : Yet another authentication Request
Bob <- Alice : Yet another authentication Response
@enduml
Your startnumber can also be a 2 or 3 digit sequence using a field delimiter such as ., ;, ,, : or a mix of these. For example: 1.1.1 or 1.1:1. Automatically the last digit will increment. To increment the first digit, use: autonumber inc A. To increment the second digit, use: autonumber inc B.
@startuml
autonumber 1.1.1
Alice -> Bob: Authentication request
Bob --> Alice: Response
autonumber inc A
'Now we have 2.1.1
Alice -> Bob: Another authentication request
Bob --> Alice: Response
autonumber inc B
'Now we have 2.2.1
Alice -> Bob: Another authentication request
Bob --> Alice: Response
autonumber inc A
'Now we have 3.1.1
Alice -> Bob: Another authentication request
autonumber inc B
'Now we have 3.2.1
Bob --> Alice: Response
@enduml
Page Title, Header and Footer
The title keyword is used to add a title to the page. Pages can display headers and footers using header and footer.
@startuml
header Page Header
footer Page %page% of %lastpage%
title Example Title
Alice -> Bob : message 1
Alice -> Bob : message 2
@enduml
Splitting diagrams
The newpage keyword is used to split a diagram into several images. You can put a title for the new page just after the newpage keyword. This title overrides the previously specified title if any. This is very handy with Word to print long diagram on several pages. (Note: this really does work. Only the first page is shown below, but it is a display artifact.)
@startuml
Alice -> Bob : message 1
Alice -> Bob : message 2
newpage
Alice -> Bob : message 3
Alice -> Bob : message 4
newpage A title for the\nlast page
Alice -> Bob : message 5
Alice -> Bob : message 6
@enduml
Grouping message
It is possible to group messages together using the following keywords:
alt/else
opt
loop
par
break
critical
group, followed by a text to be displayed
It is possible to add a text that will be displayed into the header (for group, see next paragraph 'Secondary group label'). The end keyword is used to close the group. Note that it is possible to nest groups.
@startuml
Alice -> Bob: Authentication Request
alt successful case
Bob -> Alice: Authentication Accepted
else some kind of failure
Bob -> Alice: Authentication Failure
group My own label
Alice -> Log : Log attack start
loop 1000 times
Alice -> Bob: DNS Attack
end
Alice -> Log : Log attack end
end
else Another type of failure
Bob -> Alice: Please repeat
end
@enduml
Secondary group label
For group, it is possible to add, between[ and ], a secondary text or label that will be displayed into the header.
@startuml
Alice -> Bob: Authentication Request
Bob -> Alice: Authentication Failure
group My own label [My own label 2]
Alice -> Log : Log attack start
loop 1000 times
Alice -> Bob: DNS Attack
end
Alice -> Log : Log attack end
end
@enduml
It is possible to put notes on message using the note left or note right keywords just after the message. You can have a multi-line note using the end note keywords.
@startuml
Alice->Bob : hello
note left: this is a first note
Bob->Alice : ok
note right: this is another note
Bob->Bob : I am thinking
note left
a note
can also be defined
on several lines
end note
@enduml
Some other notes
It is also possible to place notes relative to participant with note left of , note right of or note over keywords. It is possible to highlight a note by changing its background color. You can also have a multi-line note using the end note keywords.
@startuml
participant Alice
participant Bob
note left of Alice #aqua
This is displayed
left of Alice.
end note
note right of Alice: This is displayed right of Alice.
note over Alice: This is displayed over Alice.
note over Alice, Bob #FFAAAA: This is displayed\n over Bob and Alice.
note over Bob, Alice
This is yet another
example of
a long note.
end note
@enduml
Changing notes shape [hnote, rnote]
You can use hnote and rnote keywords to change note shapes :
hnote for hexagonal note;
rnote for rectangle note.
@startuml
caller -> server : conReq
hnote over caller : idle
caller <- server : conConf
rnote over server
"r" as rectangle
"h" as hexagon
endrnote
rnote over server
this is
on several
lines
endrnote
hnote over caller
this is
on several
lines
endhnote
@enduml
You can directly make a note over all participants, with the syntax:
note across: note_description
@startuml
Alice->Bob:m1
Bob->Charlie:m2
note over Alice, Charlie: Old method for note over all part. with:\n ""note over //FirstPart, LastPart//"".
note across: New method with:\n""note across""
Bob->Alice
hnote across:Note across all part.
@enduml
@startuml
participant Alice
participant "The **Famous** Bob" as Bob
Alice -> Bob : hello --there--
... Some ~~long delay~~ ...
Bob -> Alice : ok
note left
This is **bold**
This is //italics//
This is ""monospaced""
This is --stroked--
This is __underlined__
This is ~~waved~~
end note
Alice -> Bob : A //well formatted// message
note right of Alice
This is <back:cadetblue><size:18>displayed</size></back>
__left of__ Alice.
end note
note left of Bob
<u:red>This</u> is <color #118888>displayed</color>
**<color purple>left of</color> <s:red>Alice</strike> Bob**.
end note
note over Alice, Bob
<w:#FF33FF>This is hosted</w> by <img sourceforge.jpg>
end note
@enduml
Divider or separator
If you want, you can split a diagram using == separator to divide your diagram into logical steps.
@startuml
== Initialization ==
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response
== Repetition ==
Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
@enduml
Reference
You can use reference in a diagram, using the keyword ref over.
@startuml
participant Alice
actor Bob
ref over Alice, Bob : init
Alice -> Bob : hello
ref over Bob
This can be on
several lines
end ref
@enduml
Delay
You can use ... to indicate a delay in the diagram. And it is also possible to put a message with this delay.
@startuml
Alice -> Bob: Authentication Request
...
Bob --> Alice: Authentication Response
...5 minutes later...
Bob --> Alice: Good Bye !
@enduml
Text wrapping
To break long messages, you can manually add \n in your text. Another option is to use maxMessageSize setting:
@startuml
skinparam maxMessageSize 50
participant a
participant b
a -> b :this\nis\nmanually\ndone
a -> b :this is a very long message on several words
@enduml
Space
You can use ||| to indicate some spacing in the diagram. It is also possible to specify a number of pixel to be used.
@startuml
Alice -> Bob: message 1
Bob --> Alice: ok
|||
Alice -> Bob: message 2
Bob --> Alice: ok
||45||
Alice -> Bob: message 3
Bob --> Alice: ok
@enduml
Lifeline Activation and Destruction
The activate and deactivate are used to denote participant activation. Once a participant is activated, its lifeline appears. The activate and deactivate apply on the previous message. The destroy denote the end of the lifeline of a participant.
@startuml
participant User
User -> A: DoWork
activate A
A -> B: << createRequest >>
activate B
B -> C: DoWork
activate C
C --> B: WorkDone
destroy C
B --> A: RequestCreated
deactivate B
A -> User: Done
deactivate A
@enduml
Nested lifeline can be used, and it is possible to add a color on the lifeline.
@startuml
participant User
User -> A: DoWork
activate A #FFBBBB
A -> A: Internal call
activate A #DarkSalmon
A -> B: << createRequest >>
activate B
B --> A: RequestCreated
deactivate B
deactivate A
A -> User: Done
deactivate A
@enduml
Autoactivation is possible and works with the return keywords:
@startuml
autoactivate on
alice -> bob : hello
bob -> bob : self call
bill -> bob #005500 : hello from thread 2
bob -> george ** : create
return done in thread 2
return rc
bob -> george !! : delete
return success
@enduml
Return
Command return generates a return message with optional text label. The return point is that which caused the most recent life-line activation. The syntax is return label where label if provided is any string acceptable for conventional messages.
@startuml
Bob -> Alice : hello
activate Alice
Alice -> Alice : some action
return bye
@enduml
Participant creation
You can use the create keyword just before the first reception of a message to emphasize the fact that this message is actually creating this new object.
@startuml
Bob -> Alice : hello
create Other
Alice -> Other : new
create control String
Alice -> String
note right : You can also put notes!
Alice --> Bob : ok
@enduml
Shortcut syntax for activation, deactivation, creation
Immediately after specifying the target participant, the following syntax can be used:
++ Activate the target (optionally a #color may follow this)
-- Deactivate the source
** Create an instance of the target
!! Destroy an instance of the target
@startuml
alice -> bob ++ : hello
bob -> bob ++ : self call
bob -> bib ++ #005500 : hello
bob -> george ** : create
return done
return rc
bob -> george !! : delete
return success
@enduml
Then you can mix activation and deactivation, on same line:
@startuml
alice -> bob ++ : hello1
bob -> charlie --++ : hello2
charlie --> alice -- : ok
@enduml
@startuml
@startuml
alice -> bob --++ #gold: hello
bob -> alice --++ #gold: you too
alice -> bob --: step1
alice -> bob : step2
@enduml
@enduml
You can use incoming or outgoing arrows if you want to focus on a part of the diagram. Use square brackets to denote the left "[" or the right "]" side of the diagram.
@startuml
[-> A: DoWork
activate A
A -> A: Internal call
activate A
A ->] : << createRequest >>
A<--] : RequestCreated
deactivate A
[<- A: Done
deactivate A
@enduml
You can also have the following syntax:
@startuml
participant Alice
participant Bob #lightblue
Alice -> Bob
Bob -> Carol
...
[-> Bob
[o-> Bob
[o->o Bob
[x-> Bob
...
[<- Bob
[x<- Bob
...
Bob ->]
Bob ->o]
Bob o->o]
Bob ->x]
...
Bob <-]
Bob x<-]
@enduml
Short arrows for incoming and outgoing messages
You can have short arrows with using ?.
@startuml
?-> Alice : ""?->""\n**short** to actor1
[-> Alice : ""[->""\n**from start** to actor1
[-> Bob : ""[->""\n**from start** to actor2
?-> Bob : ""?->""\n**short** to actor2
Alice ->] : ""->]""\nfrom actor1 **to end**
Alice ->? : ""->?""\n**short** from actor1
Alice -> Bob : ""->"" \nfrom actor1 to actor2
@enduml
With teoz usage it is possible to add anchors to the diagram and use the anchors to specify duration time.
@startuml
!pragma teoz true
{start} Alice -> Bob : start doing things during duration
Bob -> Max : something
Max -> Bob : something else
{end} Bob -> Alice : finish
{start} <-> {end} : some time
@enduml
Stereotypes and Spots
It is possible to add stereotypes to participants using << and >>. In the stereotype, you can add a spotted character in a colored circle using the syntax (X,color).
@startuml
participant "Famous Bob" as Bob << Generated >>
participant Alice << (C,#ADD1B2) Testable >>
Bob->Alice: First message
@enduml
By default, the guillemet character is used to display the stereotype. You can change this behavious using the skinparam guillemet:
@startuml
skinparam guillemet false
participant "Famous Bob" as Bob << Generated >>
participant Alice << (C,#ADD1B2) Testable >>
Bob->Alice: First message
@enduml
@startuml
participant Bob << (C,#ADD1B2) >>
participant Alice << (C,#ADD1B2) >>
Bob->Alice: First message
@enduml
@startuml
title __Simple__ **communication** example
Alice -> Bob: Authentication Request
Bob -> Alice: Authentication Response
@enduml
You can add newline using \n in the title description.
@startuml
title __Simple__ communication example\non several lines
Alice -> Bob: Authentication Request
Bob -> Alice: Authentication Response
@enduml
You can also define title on several lines using title and end title keywords.
@startuml
title
<u>Simple</u> communication example
on <i>several</i> lines and using <font color=red>html</font>
This is hosted by <img:sourceforge.jpg>
end title
Alice -> Bob: Authentication Request
Bob -> Alice: Authentication Response
@enduml
Participants encompass
It is possible to draw a box around some participants, using box and end box commands. You can add an optional title or a optional background color, after the box keyword.
@startuml
box "Internal Service" #LightBlue
participant Bob
participant Alice
end box
participant Other
Bob -> Alice : hello
Alice -> Other : hello
@enduml
Removing Foot Boxes
You can use the hide footbox keywords to remove the foot boxes of the diagram.
@startuml
hide footbox
title Foot Box removed
Alice -> Bob: Authentication Request
Bob --> Alice: Authentication Response
@enduml
Skinparam
You can use the skinparam command to change colors and fonts for the drawing. You can use this command:
In the diagram definition, like any other commands,
You can also change other rendering parameter, as seen in the following examples:
@startuml
skinparam sequenceArrowThickness 2
skinparam roundcorner 20
skinparam maxmessagesize 60
skinparam sequenceParticipant underline
actor User
participant "First Class" as A
participant "Second Class" as B
participant "Last Class" as C
User -> A: DoWork
activate A
A -> B: Create Request
activate B
B -> C: DoWork
activate C
C --> B: WorkDone
destroy C
B --> A: Request Created
deactivate B
A --> User: Done
deactivate A
@enduml
@startuml
skinparam backgroundColor #EEEBDC
skinparam handwritten true
skinparam sequence {
ArrowColor DeepSkyBlue
ActorBorderColor DeepSkyBlue
LifeLineBorderColor blue
LifeLineBackgroundColor #A9DCDF
ParticipantBorderColor DeepSkyBlue
ParticipantBackgroundColor DodgerBlue
ParticipantFontName Impact
ParticipantFontSize 17
ParticipantFontColor #A9DCDF
ActorBackgroundColor aqua
ActorFontColor DeepSkyBlue
ActorFontSize 17
ActorFontName Aapex
}
actor User
participant "First Class" as A
participant "Second Class" as B
participant "Last Class" as C
User -> A: DoWork
activate A
A -> B: Create Request
activate B
B -> C: DoWork
activate C
C --> B: WorkDone
destroy C
B --> A: Request Created
deactivate B
A --> User: Done
deactivate A
@enduml
Changing padding
It is possible to tune some padding settings.
@startuml
skinparam ParticipantPadding 20
skinparam BoxPadding 10
box "Foo1"
participant Alice1
participant Alice2
end box
box "Foo2"
participant Bob1
participant Bob2
end box
Alice1 -> Bob1 : hello
Alice1 -> Out : out
@enduml
Appendix: Examples of all arrow type
Normal arrow
@startuml
participant Alice as a
participant Bob as b
a -> b : ""-> ""
a ->> b : ""->> ""
a -\ b : ""-\ ""
a -\\ b : ""-\\\\""
a -/ b : ""-/ ""
a -// b : ""-// ""
a ->x b : ""->x ""
a x-> b : ""x-> ""
a o-> b : ""o-> ""
a ->o b : ""->o ""
a o->o b : ""o->o ""
a <-> b : ""<-> ""
a o<->o b : ""o<->o""
a x<->x b : ""x<->x""
a ->>o b : ""->>o ""
a -\o b : ""-\o ""
a -\\o b : ""-\\\\o""
a -/o b : ""-/o ""
a -//o b : ""-//o ""
a x->o b : ""x->o ""
@enduml
Incoming and outgoing messages (with '[', ']')
Incoming messages (with '[')
@startuml
participant Alice as a
participant Bob as b
[-> b : ""[-> ""
[->> b : ""[->> ""
[-\ b : ""[-\ ""
[-\\ b : ""[-\\\\""
[-/ b : ""[-/ ""
[-// b : ""[-// ""
[->x b : ""[->x ""
[x-> b : ""[x-> ""
[o-> b : ""[o-> ""
[->o b : ""[->o ""
[o->o b : ""[o->o ""
[<-> b : ""[<-> ""
[o<->o b : ""[o<->o""
[x<->x b : ""[x<->x""
[->>o b : ""[->>o ""
[-\o b : ""[-\o ""
[-\\o b : ""[-\\\\o""
[-/o b : ""[-/o ""
[-//o b : ""[-//o ""
[x->o b : ""[x->o ""
@enduml
Outgoing messages (with ']')
@startuml
participant Alice as a
participant Bob as b
a ->] : ""->] ""
a ->>] : ""->>] ""
a -\] : ""-\] ""
a -\\] : ""-\\\\]""
a -/] : ""-/] ""
a -//] : ""-//] ""
a ->x] : ""->x] ""
a x->] : ""x->] ""
a o->] : ""o->] ""
a ->o] : ""->o] ""
a o->o] : ""o->o] ""
a <->] : ""<->] ""
a o<->o] : ""o<->o]""
a x<->x] : ""x<->x]""
a ->>o] : ""->>o] ""
a -\o] : ""-\o] ""
a -\\o] : ""-\\\\o]""
a -/o] : ""-/o] ""
a -//o] : ""-//o] ""
a x->o] : ""x->o] ""
@enduml
Short incoming and outgoing messages (with '?')
Short incoming (with '?')
@startuml
participant Alice as a
participant Bob as b
a -> b : //Long long label//
?-> b : ""?-> ""
?->> b : ""?->> ""
?-\ b : ""?-\ ""
?-\\ b : ""?-\\\\""
?-/ b : ""?-/ ""
?-// b : ""?-// ""
?->x b : ""?->x ""
?x-> b : ""?x-> ""
?o-> b : ""?o-> ""
?->o b : ""?->o ""
?o->o b : ""?o->o ""
?<-> b : ""?<-> ""
?o<->o b : ""?o<->o""
?x<->x b : ""?x<->x""
?->>o b : ""?->>o ""
?-\o b : ""?-\o ""
?-\\o b : ""?-\\\\o ""
?-/o b : ""?-/o ""
?-//o b : ""?-//o ""
?x->o b : ""?x->o ""
@enduml
Short outgoing (with '?')
@startuml
participant Alice as a
participant Bob as b
a -> b : //Long long label//
a ->? : ""->? ""
a ->>? : ""->>? ""
a -\? : ""-\? ""
a -\\? : ""-\\\\?""
a -/? : ""-/? ""
a -//? : ""-//? ""
a ->x? : ""->x? ""
a x->? : ""x->? ""
a o->? : ""o->? ""
a ->o? : ""->o? ""
a o->o? : ""o->o? ""
a <->? : ""<->? ""
a o<->o? : ""o<->o?""
a x<->x? : ""x<->x?""
a ->>o? : ""->>o? ""
a -\o? : ""-\o? ""
a -\\o? : ""-\\\\o?""
a -/o? : ""-/o? ""
a -//o? : ""-//o? ""
a x->o? : ""x->o? ""
@enduml
Specific SkinParameter
By default
@startuml
Bob -> Alice : hello
Alice -> Bob : ok
@enduml
LifelineStrategy
nosolid (by default)
@startuml
skinparam lifelineStrategy nosolid
Bob -> Alice : hello
Alice -> Bob : ok
@enduml
Hitchhiker's Guide
