Mermaid Sequence Diagrams

[Actor][Arrow][Actor]:Message text

Arrows

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)

Samples

sequenceDiagram
    Alice->>John: Hello John, how are you?
    John-->>Alice: Great!
    Alice-)John: See you later!

Participants

sequenceDiagram
    participant Alice
    participant Bob
    Alice->>Bob: Hi Bob
    Bob-->Alice: Hi Alice

Actors

sequenceDiagram
    actor Alice
    actor Bob
    Alice->>Bob: Hi Bob
    Bob->>Alice: Hi Alice

Alias

sequenceDiagram
    participant A as Alice
    participant J as John
    A->>J: Hello John, how are you?
    J->>A: Great!

Group

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?

Activations

sequenceDiagram
    Alice->>John: Hello John, how are you?
    activate John
    John-->>Alice: Great!
    deactivate John
    ## short
    Alice->>+John: Hello John, how are you?
    John-->>-Alice: Great!
    ## Activations can be stacked for same actor
    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

sequenceDiagram
    participant J as John
    participant A as Alice
    Note right of J: Text right of J
    Note left of J: Note left of J
    A->J: Hello John, how are you?
    Note over A,J: A typical interaction 
    Note over A,J: Under/below unavailable<br/>on two lines 

Loop

sequenceDiagram
    Alice->John: Hello John, how are you?
    loop Every minute
        John-->Alice: Great!
    end

Alternative Paths

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

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!

Nested

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

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
    critical Establish a connection to the DB
        Service-->DB: connect (no options)
    end

Break

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

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.

Autonumber

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!

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