Sequence diagrams

Basics

Messages send in order; par branches run together. Arrows: ->> solid, -->> reply, -x lost, -) async; +/- after the arrow activates/deactivates. wait 1s adds a pause.

sequenceDiagram
  autonumber
  actor U as User
  participant App
  participant IdP as Identity provider
  database DB
  U->>App: Click "Sign in"
  App->>IdP: Redirect /authorize
  IdP->>U: Login page
  U->>IdP: Credentials
  alt valid
    IdP-->>App: code
    App->>+IdP: POST /token
    IdP-->>-App: access_token
    App->>DB: upsert user
    App-->>U: Signed in
  else invalid
    IdP-->>U: Try again
  end

Frames

sequenceDiagram
  participant C as Client
  participant S as Server
  C->>S: SYN
  S->>C: SYN-ACK
  C->>S: ACK
  Note over C,S: connection established
  par
    C->>S: data
  and
    S->>C: data
  end
  C-)S: FIN