# Sequence Diagram (BlockDiag)

SeqDiag (part of Blockdiag) lets you describe interactions between participants over time as text, and automatically renders them as sequence diagrams - the kind used in UML to show message passing between objects or systems.

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![Sequence Diagram](https://diagrams.gocapable.com/images/att1226408067.svg)

```
seqdiag {
  browser  -> webserver [label = "GET /seqdiag/svg/base64"];
  webserver  -> processor [label = "Convert text to image"];
  webserver <-- processor;
  browser <-- webserver;
}

```