d2

Compile and render a D2 source file into an output file

$ d2 [path/to/input_file.d2] [path/to/output_file.ext]

$ d2 [[-w|--watch]] [path/to/input_file.d2] [path/to/output_file.ext]

$ d2 fmt [path/to/input_file.d2]

$ d2 themes

$ d2 [[-t|--theme]] [theme_id] [path/to/input_file.d2] [path/to/output_file.ext]

$ d2 [[-s|--sketch]] true [path/to/input_file.d2] [path/to/output_file.ext]

d2 [OPTIONS] INPUT_FILE [OUTPUT_FILE]

-t, --theme
    Sets the diagram's visual theme (e.g., 'default', 'dark', 'sketchy', 'neutral', 'gray', 'cool').

-l, --layout
    Specifies the graph layout engine to use (e.g., 'dagre', 'elk').

-o, --output
    Defines the output file path and format (e.g., 'diagram.svg', 'doc.png'). If omitted, defaults to stdout or a derived filename.

--watch
    Monitors the input file for changes and recompiles automatically. Useful for live preview.

-p, --pad
    Sets the padding (in pixels) around the generated diagram.

--sketch
    Enables a hand-drawn, sketchy style for the diagram, overriding the theme's default.

--font
    Specifies the font family to be used in the diagram (e.g., 'Inter', 'Cascadia Code').

--target-id
    Compiles only the diagram with the specified ID in a multi-diagram input file.

--animate
    Enables animation for web output, useful for interactive diagrams (e.g., when embedding in HTML).

--config
    Specifies a TOML configuration file for D2 settings, allowing global or project-specific defaults.

--force-update
    Forces recompilation even if inputs haven't changed, bypassing cache.

-V, --version
    Prints the D2 version information and exits.

-h, --help
    Displays help message and exits.

The d2 command-line interface compiles D2 diagramming language source files into various graphical formats such as SVG, PNG, PDF, and HTML.

D2 is an open-source, text-based diagramming language designed for creating diagrams that can be version-controlled, easily integrated into CI/CD pipelines, and rendered consistently across different environments. It aims to simplify the process of creating complex diagrams by defining them programmatically rather than through graphical user interfaces.

It leverages various graph layout engines (like Dagre and ELK) to automatically arrange elements, allowing users to focus on the logical structure and content of their diagrams. D2 supports numerous customization options, including themes, fonts, and sketch modes.

d2 is not a standard Unix/Linux utility and must be installed separately (e.g., via `brew`, `npm`, or by downloading binaries). It relies on external layout engines, which might require additional configuration or dependencies for optimal performance. While powerful, its text-based nature might have a learning curve for users accustomed to GUI-based diagramming tools.

D2 embodies the 'diagrams as code' principle, allowing diagrams to be stored, versioned, and diffed just like source code. This enables seamless integration into Git workflows, making diagram updates traceable, collaborative, and part of documentation-as-code initiatives.

D2 is designed with extensibility in mind, allowing users to define custom shapes, styles, and even integrate with external data sources or APIs to generate dynamic diagrams. This flexibility makes it suitable for a wide range of use cases beyond simple static diagrams.

The d2 project was open-sourced by Terrastruct in 2022, aiming to provide a modern, versatile, and developer-friendly alternative for creating diagrams as code. It quickly gained traction within the developer community for its elegant syntax and robust features, becoming a popular choice for technical documentation and system design. Its development continues with a focus on improving layout quality, adding more output formats, and enhancing integration capabilities with various tools and platforms.

graphviz(1) - `dot` command for Graphviz diagramming, a foundational tool for graph visualization., plantuml - Another popular text-to-diagram generation tool, often invoked via a Java JAR.