MarkView (Open-Source Edition)

A lightweight, open-source markdown viewer for Chrome, Edge and other Chromium browsers. It is the core rendering engine of MarkView, released under the MIT License for auditing, self-hosting and restricted environments.

Open a .md file in the browser, from disk or from a link, and MarkView renders it as a formatted document in place of the raw text.

Features

Rendering

• GitHub Flavored Markdown: tables, task lists, strikethrough, footnotes, autolinks
• GitHub-style alerts: Note, Tip, Important, Warning, Caution
• Extended syntax: subscript, superscript, inserted and highlighted text, abbreviations, definition lists, custom containers, emoji shortcodes
• Syntax highlighting with highlight.js (its common language set), a copy button and 14 color themes
• Mermaid diagrams, with zoom and download
• KaTeX math, inline and display

Reading

• Light and dark themes
• Table of contents for H1–H3 headings, in a resizable sidebar
• Raw markdown view, print styles, image viewer, font selection
• Auto-refresh when the file changes
• Recent documents and settings in the toolbar popup
• Keyboard shortcuts
• Interface in 12 languages

Files

• .md, .markdown, .mkd and .mdx, on file:// and http(s):// URLs

Install from source

Requirements: Node.js 20 or later, pnpm 8 or later.

git clone https://github.com/markview-app/markview.git
cd markview
pnpm install
pnpm run build

Then load the unpacked extension:

1. Open chrome://extensions/ (or edge://extensions/)
2. Turn on Developer mode
3. Click Load unpacked and select the extension/ folder
4. To view local files, open the extension's Details and turn on Allow access to file URLs

pnpm run build also writes a zip of the same build to dist/.

Privacy

All rendering happens in the browser tab. MarkView has no analytics, telemetry or crash reporting, and it never sends your documents anywhere. The only network requests it makes are:

Request	When
The document's own URL and images it links to	Opening a document; auto-refresh polls the document URL
Google Fonts (fonts.googleapis.com)	Only after you choose a font other than the default; the font name is part of the request

Permissions

• storage: saves your settings and the recent-documents list in the browser
• Host access to file:///* and *://*/*: lets the extension render markdown files at any address, and lets its background worker fetch the open document (auto-refresh) and its images when the page itself is not allowed to

Scope

This edition keeps to a small, stable core. Bug fixes, security fixes, documentation, translations and accessibility improvements are welcome. New features outside core markdown rendering are generally not accepted, and the project does not publish a roadmap. See Contributing before opening a pull request.

Documentation

• Development guide: build, test and project layout
• Architecture: how a document goes from raw text to rendered page
• Contributing
• Security policy
• Changelog

Support

• Bugs in this edition: open an issue
• Questions: Discussions
• Security vulnerabilities: see SECURITY.md, not public issues

License

MIT. Third-party libraries keep their own licenses; see package.json for the list.

MarkView for Chrome & Edge

This repository is the open-source core. MarkView is also available from the Chrome Web Store and Microsoft Edge Add-ons as a separately developed extension that adds folder navigation, presentation mode, and HTML and Word export. Its code is not part of this repository, and this repository does not track its features.

Issues with the store version go to markview-app/support.

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Website • Chrome Web Store • Edge Add-ons