Markdown ZenUML sequence maker

Draw a sequence by writing it as code. Name your participants, then write each call and its return, and ZenUML lays out the lifelines, arrows and activation bars for you inline in your document.

ZenUML sequence syntax

A ZenUML block starts with the word zenuml. You list your participants, then write the story as calls between them. A call reads like code: one object calls a method on another, and the body of that call goes in braces. Here is each piece you can write.

Participants and messages

Declare a participant with a stereotype like @Actor or @Database, then send a plain message with A->B: text.

You write

zenuml
  @Actor Customer
  @Boundary Web
  Customer->Web: open page
  Web->Customer: show form

You get

Synchronous calls and returns

Write a method call as A->B.method(). Put the work it triggers in braces, and end with return value to send a result back.

You write

zenuml
  @Actor Customer
  @Boundary Web
  @Control OrderService
  Customer->Web.checkout() {
    Web->OrderService.create() {
      return orderId
    }
    return page
  }

You get

Creating an object

Write new B to create an object, or x = new B() to name the thing you made.

You write

zenuml
  @Control OrderService
  OrderService->OrderService.build() {
    order = new Order()
    return order
  }

You get

Cheat sheet

Write this	You get
`zenuml`	Start a ZenUML sequence
`title Text`	Title the diagram
`@Actor Name`	A participant drawn as an actor
`@Boundary Name`	A boundary (edge of the system)
`@Control Name`	A control (coordinating logic)
`@Entity Name`	An entity (a thing being worked on)
`@Database Name`	A database
`@Queue Name`	A message queue
`A->B: text`	A plain message from A to B
`A->B.method()`	A synchronous call to B.method()
`A->B.method() { … }`	A call whose body is the nested messages
`return value`	Return a result from the current call
`A->A: text`	A self message
`new B`	Create an object of B
`x = new B()`	Create B and name it x