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Drawio for Obsidian

Embed, preview, and edit draw.io (diagrams.net) diagrams directly in your notes. Previews render fully offline on every platform, and diagrams are stored as readable, diff-friendly XML.

Highlights

• Three surfaces, one plugin — inline ```drawio code blocks, standalone .drawio files (Excalidraw-style: the editor lives right in the file's tab), and ![[file.drawio]] embeds. All three render live SVG previews in both editing and reading views; click any preview to edit.
• Offline previews, always — previews are produced by drawio's own viewer bundled into the plugin: no iframe, no network, on desktop and mobile alike.
• Offline editor, optionally — the editor defaults to a bundled, fully offline drawio build served from a local server. Store installs don't include the bundle (~145 MB); install it with one click from the plugin settings, or switch the editor source to Online.
• Readable, git-friendly storage — diagrams are saved as uncompressed, pretty-printed XML rather than a compressed blob, so diffs, sync, and version history stay meaningful.
• Multi-page aware — multi-page diagrams get a compact page switcher (‹ 2 / 5 ›) under the preview, and ![[file.drawio#Page-2]] opens the embed on the page named "Page-2".
• Fits into Obsidian — follows your light/dark theme, keeps working in popped-out windows, sanitizes rendered SVG before insertion, and supports phones and tablets (preview-only there — see Platform support).

Quick start

1. Install Drawio from the community plugin store and enable it (requires Obsidian 1.4.0+).
2. Click the ribbon button, run the Create new diagram command, or right-click a folder in the file explorer and choose New drawio diagram.
3. A new .drawio file opens with the editor embedded in its tab. Draw — changes autosave back to the file.

The editor needs one of: the offline editor installed (one click in settings, ~53 MB download), or Editor source → Online in the plugin settings. See Offline editor.

Usage

All render as previews in both editing and reading views, and every edit autosaves back to its source — the code block's XML or the diagram file. Embeds re-render automatically when the underlying file changes.

Dual-format files (.drawio.svg / .drawio.png): the file is a standard SVG or PNG image with the diagram embedded inside — it displays as a plain image everywhere (GitHub, exports, other tools, Obsidian's own image view and embeds) while staying fully editable here. Set New diagram format in the settings to create them by default; edit via the file's context menu (Edit drawio diagram) or the Edit diagram in the current image file command. Each save re-exports the image part, keeping picture and diagram in sync. Same format as the VS Code drawio extension, so the files are interchangeable.

Multi-page diagrams: previews show a page switcher (‹ N / M ›) below the diagram when it has more than one page. ![[file.drawio#Page-2]] selects the initial page by its name (falling back to the first page if no page matches). Opening the editor always shows all page tabs.

Converting between code blocks and files: two palette commands switch a diagram between its two source forms (they work on mobile too). Extract diagram code block to file — with the cursor inside a ```drawio block — moves the block's XML into a new <note name> diagram.drawio file next to the note (numbered 2, 3, … if that name is taken) and replaces the block with an embed. **Convert diagram embed to code block** — with the cursor on a line containing a ![[….drawio]] embed — replaces the embed with a ```drawio block holding the file's XML; the file itself is kept, and any #Page-… or |alias part of the link is dropped.

Exporting plain images (desktop): the Export diagram as SVG and Export diagram as PNG commands — also on the context menu of .drawio and .drawio.svg/.drawio.png files — write a plain .svg/.png image of the diagram (without the embedded diagram data) next to the source file, numbered 2, 3, … if the name is taken.

Platform support

Phones and tablets behave identically: previews everywhere, no editing. Tapping a preview there shows a notice that editing needs desktop; the creation entry points are hidden as well, since their sole purpose is opening the editor.

Settings

On mobile, only Preview alignment and Follow Obsidian theme are shown — the other settings configure the desktop editor.

Network use

• Previews never use the network. They are rendered by drawio's viewer.min.js, which is bundled into the plugin.
• With the bundled offline editor, the plugin makes no network requests at all — the editor is served from a local 127.0.0.1 HTTP server.
• When the bundle isn't installed, Offline mode shows an install prompt instead of silently going online. If you choose Online (or a Custom URL), the editor UI is loaded from that origin. Your diagram content still stays on your device — it is passed to the editor in the page and is not uploaded; only the editor's assets are fetched.

Offline editor (optional)

A store install ships without the offline drawio webapp (it is ~145 MB, beyond store limits). To install it, open Settings → Drawio, select Editor source → Offline (bundled webapp), and click Install — a one-time ~53 MB download from GitHub; editing is fully offline afterwards. After a plugin update that bumps the bundled drawio version, the same row shows Update until the installed webapp matches again.

No network on the vault machine? Every release also ships drawio-editor-<version>-offline.zip — the complete plugin folder with the webapp already inside. Download it from the releases page on a connected machine and, with Obsidian closed, extract it into <vault>/.obsidian/plugins/ (it contains a single drawio-editor/ folder; extracting over an existing install is fine). Then enable the plugin and select Editor source → Offline (bundled webapp).

Building from source also works and produces the same layout: run npm run fetch-drawio before npm run build and copy the webapp/ folder alongside main.js (see Development below).

Notes & limitations

• Editing is desktop-only — it needs the iframe-based drawio editor and, in Offline mode, a local HTTP server. Mobile gets previews (see Platform support).
• Bundle size: main.js is 2.5 MB because drawio's viewer (2.4 MB) is inlined for offline previews. This is expected.
• Security: rendered SVG previews are sanitized before insertion — script/embedding elements, inline event handlers, script-bearing URL schemes, external <use> references, SMIL injection, and dangerous CSS are removed, while drawio's foreignObject text labels are preserved. The bundled viewer runs without injecting any <script> element, and its one external-script loader (an unused MathJax-from-CDN helper) is stripped at build time, so previews fetch and execute no external code. In Offline mode the local server binds to 127.0.0.1 only and serves solely the bundled webapp/ directory.

Development

npm install
npm run fetch-drawio   # once per clone: fetch the drawio webapp + preview viewer
npm run dev            # watch build
npm test               # unit tests (vitest)
npm run build          # type-check + production bundle

Bug reports and pull requests are welcome — please open an issue first for larger changes.

License

MIT