Installer
RecommendedDiagramon_3.13.1_x64-setup.exe
Guided setup, and the app checks for updates on its own afterwards (the update package is this same installer).
Download
v3.13.1 · Local-first · fully usable without an account
The multi-format diagram editor AI understands best
Diagram source files are plain text on disk —
AI reads them and edits them precisely, and so can you.
Mermaid, Graphviz DOT, D2, drawio and Excalidraw are supported (.mmd / .mermaid files and more). This site only handles accounts and cloud source storage, so you can sync your files across machines.
The free plan works right away; cloud storage and AI features need a membership. The desktop app needs no account — just download it and start drawing.
Latest release
v3.13.1
Human + AI, one file
One file: AI edits it precisely — and so do you
All five formats are plain text on disk. AI and you edit the same file — there is no divide between 'AI output' and 'my diagram'.
AI understands and edits
Reads the full source and pinpoints rows and columns; changes arrive as a diff you approve block by block, and render errors are fed back for an automatic fix.
Plain-text source file
.mmd · .dot · .d2 · .drawio · .excalidraw — diffable, versionable, easy to sync.
Humans edit too
Type in the source pane (errors down to the column, outline, formatting) or drag on the canvas — both write back to the same body.
| Capability | AI edits precisely | Human drag editing | Diffable on disk |
|---|---|---|---|
| mermaid.live and other text tools | ✓ | — | ✓ |
| Official drawio / Excalidraw | — | ✓ | Limited |
| Diagramon | ✓ | ✓ | ✓ |
Sources are plain text: AI and you edit the same file, in the source pane or on the canvas.
Features
Everything the desktop app does, the cloud leaves alone
Editing, rendering, exporting and AI all run locally; the cloud only keeps a copy of your source files somewhere else.
Real editors for five formats
Draw drawio and Excalidraw diagrams directly in their official canvas editors — saved to disk as diffable text; edit Mermaid, DOT and D2 as source with a live preview, and export a high-resolution PNG or copy to the clipboard anytime. The sidebar manages a whole folder tree with workspace-wide search, and unsaved changes are confirmed one by one before closing.
Format conversion
Convert locally between the five formats (unsupported directions say so up front): the engine and scope are shown before converting, the report lists every unmigrated item, and AI can fill the gaps in one click.
Colors follow the structure
Nodes inside a subgraph, cluster or container share a hue, so each subsystem reads at a glance. Six schemes in one click, written into the source itself — the colors stay when you switch tools or machines.
AI generate · review · vision
Generate diagrams from plain language, review existing ones, or turn a screenshot into code. AI's changes arrive as a diff you approve block by block, and render errors are fed back for an automatic fix. Bring your own key (OpenAI-compatible, local Ollama models and more); members can use the cloud gateway.
AI conversation & memory
Keep refining across multi-turn conversations, with sessions stored per document on your machine and intact after a restart. The AI can propose to remember your preferences and terminology — effective only after you confirm. Render errors are fed back to the model for an automatic fix.
Cloud source storage
A membership feature: upload documents explicitly and organize them in a cloud folder tree. Your quota and usage are shown on the Account page, and files can be deleted at any time. The cloud only stores files and never parses them, so Mermaid, DOT, drawio and other formats all work.
Download
Download the desktop app
The two packages are identical in features: the installer updates itself, the portable zip just runs once you unzip it.
Portable zip (nothing to install)
Diagramon-3.13.1-win-x64.zip
Unzip it anywhere and run diagramon.exe; uninstalling means deleting the folder.
DownloadFormats
One editor, many diagram types
All five formats are first-class: source plus a live preview, or an official canvas editor; the cloud only stores source files and never parses them.
MermaidAvailable now
Graphviz DOTAvailable now
D2Available now
drawioAvailable now
ExcalidrawAvailable now
More in development
Quick start
Four steps
Download the desktop app and open it
The installer sets up with a double-click and ships with built-in auto-updates; a portable build is also available. The WebView2 that comes with Windows 10/11 is all you need (the installer downloads it if missing).
Start drawing right away
Create or open a .mmd file and start right away: Mermaid, DOT and D2 edit on the left with a live preview on the right, while drawio and Excalidraw are drawn directly on the canvas. No account needed for this step.
Sign up once you need AI and cross-machine sync
Register, activate your email and log in, and the desktop app can save the documents you pick to the cloud, organized in a folder tree.
Manage it all on the Account page
Check your quota and usage, download or delete cloud documents, and change your password.
Make the diagram first, decide about the cloud later
The desktop app is fully usable without logging in.
Download for Windows