SNDiagramme

SNDiagramme is a cross-platform framework and file format for documenting and rendering diagrams, focusing on network diagrams, circuit schematics, and flowcharts. It uses a graph-based model with nodes, edges, and attributes to describe structures and layouts. It supports multiple rendering backends and is intended to facilitate exchange of diagram data between tools.

The SNDiagramme file format, typically with .sndg extension, encodes diagrams as a JSON-like structure with sections for nodes, edges, layouts, styles, and metadata. It supports hierarchical grouping, layered layouts, constraint-based routing, and style sheets to control appearance. It includes compatibility hooks for SVG and PNG export, and can embed external resources such as images and icons. It includes a rendering engine that can produce both static and interactive diagrams.

Originated as an open-source project in the early 2010s by a coalition of developers and researchers seeking a common standard for diagram data. It has since evolved through multiple revisions, with governance by an international contributor community. It emphasizes interoperability, extensibility, and accessible documentation.

Used in education, engineering, network design, system architecture planning, and data visualization. It supports both human-readable editing and programmatic generation via bindings in Python, JavaScript, and other languages. Tools like diagram editors, code generators, and integrated development environments integrate SNDiagramme to manage diagrams.

See also Graphviz, PlantUML, GraphML, Mermaid.