--- title: Sequence ยท Pele description: Show the messages that participants exchange over time. --- ```mermaid sequenceDiagram Alice->>John: Hello John, how are you? John-->>Alice: Great! Alice-)John: See you later! ``` ```mermaid sequenceDiagram autonumber actor Customer participant Web as Web app participant API as API gateway participant Bank Customer->>Web: Place order Web->>API: POST /orders activate API API->>Bank: Authorize payment Bank-->>API: Approved API-->>Web: 201 Created deactivate API Web-->>Customer: Order confirmed Note over Customer,Bank: One order, one transaction ``` ```mermaid --- config: theme: default look: classic --- sequenceDiagram autonumber actor Customer participant Web as Web app participant API as API gateway participant Bank Customer->>Web: Place order Web->>API: POST /orders activate API API->>Bank: Authorize payment Bank-->>API: Approved API-->>Web: 201 Created deactivate API Web-->>Customer: Order confirmed Note over Customer,Bank: One order, one transaction ``` ```mermaid sequenceDiagram participant Alice participant Bob Bob->>Alice: Hi Alice Alice->>Bob: Hi Bob ``` ```mermaid sequenceDiagram actor Alice actor Bob Alice->>Bob: Hi Bob Bob->>Alice: Hi Alice ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "boundary" } participant Bob Alice->>Bob: Request from boundary Bob->>Alice: Response to boundary ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "control" } participant Bob Alice->>Bob: Control request Bob->>Alice: Control response ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "entity" } participant Bob Alice->>Bob: Entity request Bob->>Alice: Entity response ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "database" } participant Bob Alice->>Bob: DB query Bob->>Alice: DB result ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "collections" } participant Bob Alice->>Bob: Collections request Bob->>Alice: Collections response ``` ```mermaid sequenceDiagram participant Alice@{ "type" : "queue" } participant Bob Alice->>Bob: Queue message Bob->>Alice: Queue response ``` ```mermaid sequenceDiagram participant A as Alice participant J as John A->>J: Hello John, how are you? J->>A: Great! ``` ```mermaid sequenceDiagram participant API@{ "type": "boundary" } as Public API actor DB@{ "type": "database" } as User Database participant Svc@{ "type": "control" } as Auth Service API->>Svc: Authenticate Svc->>DB: Query user DB-->>Svc: User data Svc-->>API: Token ``` ```mermaid sequenceDiagram participant API@{ "type": "boundary", "alias": "Public API" } participant Auth@{ "type": "control", "alias": "Auth Service" } participant DB@{ "type": "database", "alias": "User Database" } API->>Auth: Login request Auth->>DB: Query user DB-->>Auth: User data Auth-->>API: Access token ``` ```mermaid sequenceDiagram participant API@{ "type": "boundary", "alias": "Internal Name" } as External Name participant DB@{ "type": "database", "alias": "Internal DB" } as External DB API->>DB: Query DB-->>API: Result ``` ```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 ``` ```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 Charley? B->>C: Hello Charley, how are you? ``` ```mermaid sequenceDiagram participant Alice participant John Alice->>()John: Hello John Alice()->>John: How are you? John()->>()Alice: Great! ``` ```mermaid sequenceDiagram Alice->>John: Hello John, how are you? activate John John-->>Alice: Great! deactivate John ``` ```mermaid sequenceDiagram Alice->>+John: Hello John, how are you? John-->>-Alice: 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! ``` ```mermaid sequenceDiagram participant John Note right of John: Text in note ``` ```mermaid 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
But now in two lines ``` ```mermaid sequenceDiagram participant Alice as Alice
Johnson 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? loop Every minute John-->Alice: Great! 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 ``` ```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! ``` ```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 ``` ```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 ``` ```mermaid sequenceDiagram critical Establish a connection to the DB Service-->DB: connect end ``` ```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 ``` ```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. ``` ```mermaid sequenceDiagram Alice->>John: Hello John, how are you? %% this is a comment John-->>Alice: Great! ``` ```mermaid sequenceDiagram A->>B: I #9829; you! B->>A: I #9829; you #infin; times more! ``` ```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! ``` ```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! ``` ```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! ```