Diagram Design NotationDesign · describe · connect
Free and open source · GPLv2 or later · Sponsored by ScratchBird Software Inc.

Open source · GPLv2 or later

A shared model.
Many ways to see it.

Free, open-source diagramming for everyone. Connect diagrams, data and documents with a few words — sponsored by ScratchBird Software Inc.

Open visual designer Explore appearance toolsBrowse gallery
151 diagram profiles3 standalone utilitiesLocal browser operation

Diagram Design Notation

A model-first language. Free tools.

DDN is an open-source diagram dialect and open standard proposal. Declare data, format and views separately in plain-text .ddn files, then project one model into ERDs, DFDs, flowcharts, C4 views, matrices, charts, timelines, fishbones, decision tables, wireframes and more.

The free DDN viewer, visual designer and verifier run locally in your browser without a server or account. Use, study, modify and share DDN under GPLv2 or later.

The DDN foundation

Three tools. One connected workflow.

Open a real example, make a change, and check its rules.

Download the utilities →

Viewer

Display connected diagrams, explore views and capture snapshots. Read-only, with support for supplied live updates.

Open viewer

Visual designer

Work from an idea to a structured model with editing, legal palettes, source changes and undoable settings.

Open designer

Verifier

Check the source, references, properties and profile rules for the scope and review stage you choose.

Run verifier

A few lines are enough

Start with the idea.
Add the detail as it develops.

Name-only entities, free-form notes and provisional data are useful design material. You can add structure, check the rules and review a finished design when it is ready.

Learn the indentation-based dialect →

erd Sales
    Customer
    Order
    connect Customer to Order

Omitted settings use versioned defaults. File settings override CSS, and CSS overrides standard presentation.

DDN foundation
One workarea. Connected views.

DDN, DDNA and DDNN connect design across disciplines. Other diagramming methods keep their own symbols, connectors and verification rules.

Live render — generated in your browser

This embedded view runs the new viewer. Open the tools to select another view, inspect the source, edit a copy or check diagnostics.

Open the full viewer

Explore DDN

From the first sketch to the reference contract

The complete gallery

Real converted examples across all 151 profiles, plus chart, layout and presentation variations.

Preview · source · edit · verify

Paper, shadows and stationery

Compare paper silhouettes, coloured notes and pads, push-pins, paper clips, binder clips and tape.

Configurable vector appearances

Appearance standards and presets

Movable forms for textures, local fonts and colour; reusable user and company presets.

Light · dark · midnight · warm

Field guide

Understand what each diagram communicates, when to use it and how to review its actual source.

160 diagram and process lessons

Element and relation reference

Look up permitted roles, connection endpoints, properties and profile-specific defaults.

Generated from the adopted codex

Visual designer

Build on the viewer with editing, data and field controls, profile selection and source changes.

Single user · browser only

Embed the utilities

Use the shared runtime with a read-only viewer, a designer or an independent verifier.

Modular JavaScript APIs

Language and standard

Read the new source rules, lifecycle model, defaults hierarchy and profile boundaries.

ddn-next-1

The ScratchBird suite of systems software

DDN is the free, open-source diagramming project sponsored by ScratchBird Software Inc. The suite also includes Weaver, ScratchBird CDE and ScratchRobin, each with its own product and licensing terms.

DDN

DDN

The GPLv2-or-later language, viewer, designer and verifier for general public use.

Weaver

Weaver

The separate commercial platform for collaboration and connected design.