docu.md Markdown Viewer

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Preview Markdown. Preserve the complex parts. Export finished documents.

docu.md Markdown Viewer opens local or online Markdown as a polished reading page and exports it when you need a document people can actually use. It keeps the source file simple while preserving the parts that usually break during handoff: tables, images, code blocks, math, diagrams, themes, and document spacing.

It is built for technical documentation, engineering notes, research drafts, weekly reports, knowledge-base pages, README files, and AI-generated Markdown that needs final formatting.

Install

• Chrome / Chromium: https://chromewebstore.google.com/detail/markdown-viewer/jekhhoflgcfoikceikgeenibinpojaoi
• Microsoft Edge: https://microsoftedge.microsoft.com/addons/detail/documd-markdown-viewer/iphmkjlbnogmhofmmcahdhodiilokfca
• Firefox: https://addons.mozilla.org/firefox/addon/markdown-viewer-extension/
• Obsidian: https://community.obsidian.md/plugins/markdown-viewer-extension
• VS Code: https://marketplace.visualstudio.com/items?itemName=xicilion.markdown-viewer-extension · https://open-vsx.org/extension/xicilion/markdown-viewer-extension
• Mobile: See the mobile app docs

Node.js HTML CLI

The repository includes a headless-Chrome CLI that renders a Markdown file with the same parser, themes, math support, and diagram renderers used by the viewer. It requires Node.js 24 or newer and an installed Google Chrome browser.

npm install
npm run build:cli
npm run documd -- README.md README.html

Chrome runs headlessly and uses a temporary browser profile. A separate Chromium download is not required. Common options include:

npm run documd -- notes.md --theme technical
npm run documd -- report.md --frontmatter table --merge-empty-cells
npm run documd -- night.md night.pdf --theme midnight

It can also export just the figures and images of a document (all of them, or by number/kind), and it reports any figure or image that failed to render:

npm run documd -- report.md --assets ./figures
npm run documd -- report.md --assets ./figures --only 1,3 --format svg

The conversion exits non-zero when a figure or image did not render, naming the markdown line, the engine and the reason; --no-fail-on-error keeps the exit code at 0 when a pipeline only wants the report.

Run npm run documd -- --help for all options. Theme IDs are listed in src/themes/registry.json.

Highlights

• Clean Markdown preview for local files and supported web URLs.
• DOCX export for editable Word documents.
• PDF, self-contained HTML, and EPUB export where supported by the platform.
• Editable formulas in Word output.
• Syntax highlighting for code blocks.
• Document themes for business reports, academic writing, technical notes, reading layouts, and Chinese typography.
• Smart rendering and caching for large documents.
• Local processing for normal preview and export workflows.

Why It Exists

Markdown is fast to write and easy to version. It is also the default format for many AI assistants, developer notes, project reports, and technical drafts.

The problem appears at the handoff stage. A .md file is not always acceptable when a colleague expects a Word document, a reviewer wants a printable PDF, or a client needs a self-contained page. Copying content into another editor often means rebuilding layout, screenshots, formulas, code formatting, and tables by hand.

docu.md bridges that gap. Open the Markdown file, review the rendered result, choose a document style, and export when it is ready.

Rich Content Support

docu.md supports standard Markdown, GitHub-style tables and task lists, images, highlighted code, math formulas, SVG content, complex HTML tables, and diagrams or charts written in common text-based formats such as PlantUML, Mermaid, Vega/Vega-Lite, drawio, Canvas, Infographic, Graphviz, and ECharts.

OpenAPI 3.x and Swagger 2.0 YAML documents (.yaml / .yml) opened in the workspace or editor preview render as API references with Redoc CE: a .yaml document opens as its own source, and the preview toggle switches to the reference (panel hosts such as VS Code open the reference directly). YAML that is not an API document previews as highlighted source, with a note saying so. An openapi/swagger code fence inside Markdown stays a code block — what the preview shows is what the Word export contains. Relative $ref files use the current document's resource reader, including nested and circular references. Redoc CE is bundled locally, uses system fonts, sanitizes document HTML, and filters unsafe metadata links. Script-free HTML, EPUB, and Word exports preserve the YAML source.

That feature list appears here once because it is useful. The rest of the README focuses on workflows, platforms, and practical setup.

What You Can Do

• Open local or online Markdown files in a clean reading view.
• Export finished documents to DOCX, PDF, self-contained HTML, or EPUB where supported by the platform.
• Keep formulas editable in Word instead of flattening them into screenshots.
• Render diagrams and charts directly from Markdown source blocks.
• Preserve code highlighting, tables, images, headings, and long-form document structure.
• Switch document themes for academic, business, technical, reading, and Chinese typography needs.
• Work with local processing so your documents stay on your device.

Common Workflows

AI Draft to Shareable Document

Paste or save Markdown from an AI assistant, open it with docu.md, review the formatted result, and export a polished document for colleagues, clients, classmates, or reviewers.

Technical Notes to Documentation

Keep architecture notes, project READMEs, API drafts, and visual blocks in Markdown. Preview them with formatted code and rendered content before sharing.

Reports and Research Drafts

Use Markdown for writing speed, then export documents with tables, formulas, headings, and document themes preserved for review or submission.

Document Output

docu.md focuses on the handoff formats people ask for after the writing is done:

• DOCX for editable Word documents.
• PDF for print-ready sharing where supported.
• HTML for self-contained publishing where supported.
• EPUB for ebooks and whole-book exports where supported.
• Image/vector exports for rendered visual blocks where supported.
• XLSX for tables saved as spreadsheets where supported.

Exact output options vary by platform. See the platform docs for the environment you use.

Platforms

Platform	Best For	Docs
Chrome / Chromium	Opening local or online Markdown in the browser	Chrome docs
Microsoft Edge	Edge Add-ons installation and Edge-managed updates	Edge docs
Firefox	Firefox-based browser workflows	Firefox docs
Obsidian	Vault-native preview and export	Obsidian docs
VS Code	Editor-side preview, commands, and writing workflows	VS Code docs
Mobile	Opening and sharing Markdown on iOS and Android	Mobile docs

Privacy

Document processing is local. docu.md does not require uploading your Markdown files to a remote rendering service for normal preview and export workflows.

Getting Started

1. Install docu.md on the platform you use.
2. Open a Markdown file or choose it from your workspace.
3. Review the rendered document.
4. Pick a theme if needed.
5. Export or share the finished result.

Documentation

• Getting Started
• Feature Guide
• Platform Comparison
• FAQ
• Privacy Policy

Development Testing

See Testing Architecture and E2E Requirements for the project's test-layer boundaries, E2E rules, CI workflow, and review checklist.

After installing dependencies and building the CLI and Chrome extension, run the compatibility tests and the installed-extension E2E tests separately:

npm run test:unit
npm run test:e2e

npm test runs both suites. The extension E2E suite uses Node.js and Playwright directly, with no model-backed browser agent involved in test execution.

Open Source

docu.md Markdown Viewer is open source under GPLv3.