Custom diagrams
In addition to the C4 model diagrams, Structurizr provides support for creating ad hoc diagrams, using custom elements, based upon the same diagramming infrastructure.
Not available with a free or basic subscription
Please note that, at the moment, custom diagrams are only supported via the Structurizr for Java client library, and the Structurizr DSL. Custom diagrams will not be rendered with the free version of Structurizr.