Sequence diagram (SeqDiag)

SeqDiag trades features for brevity. An arrow is a message, a double arrow is a call with its return, and that is most of the language.

#What this example shows

• The => form, which draws a call and its return in one line.

• Explicit return labels.

• Participants ordered by first mention.

#A worked example

Open it, edit it, or copy the source below.

The source, which you can paste into a new diagram and edit:

seqdiag {
  browser  -> web    [label = "GET /orders"];
  web      => api    [label = "getOrders(userId)", return = "orders"];
  api      => db     [label = "SELECT * FROM orders", return = "rows"];
  api      -> cache  [label = "warm cache", note = "fire and forget"];
  browser <-- web    [label = "200 OK"];
}

#Making it your own

• Mention participants in the order you want them drawn.

• The => form halves the length of a long sequence.

• For activations, alt blocks and loops, use Mermaid or PlantUML.

#Related

Specialists. Borrow one when you need it.