D2 Rendering Backend¶

The D2 rendering backend maps diagrams to D2 source. It is a text-first backend: rendering to .d2 source does not require a local D2 binary, while image export delegates to an optional local D2 installation.

For portable model code, start with Portable core and backend extensions. For D2-specific behavior, use the pages in this section.

Capability table¶

Capability	Status	Where to configure
D2 source rendering	Supported for all current C4 diagram types	`Diagram.as_d2()` and `Diagram.save_as_d2()`
D2 image export	Supported through local D2 for SVG, PNG, and PDF	Renderers
Element and boundary mapping	Supported for core elements, boundaries, and deployment nodes	Core diagram classes plus `d2={...}`
Nested boundaries	Preserved as D2 containers	Core boundary and deployment node classes
Element and relationship properties	Rendered as Markdown tables when enabled	Options
Layout direction, theme, sequence shape, relationship numbering	Supported as render options	Options
Structured legends	Supported through `D2RenderOptions.legend`	Options
D2 extension fields	Supported for shapes, styles, links, tooltips, icons, classes, and local directions	Extensions
Bidirectional relationships	Rendered as two directed edges by default, or one `<->` edge	Options

Pages¶

Renderers: D2Renderer, local D2 backend, as_d2(), and save_as_d2().
Options: direction, theme, sequence diagrams, relationship numbering, properties, bidirectional edges, and legends.
Extensions: preferred d2={...} authoring syntax.
Limitations: validation behavior and degraded backend-only helpers.