markdown-browser

Markdown Browser

A Chrome extension for reading, writing, and organizing local markdown files — fast, private, and fully offline.

Features

Reading

• Local file reading via the File System Access API — no uploads, no cloud
• Sidebar file tree with collapsible folders and live filter
• Hot reload — viewer auto-refreshes when you save in an external editor
• Full-text search across all markdown files (⌘K)
• Table of contents with scroll-spy highlighting
• Syntax highlighting for JS, TS, Python, Go, Rust, SQL, CSS, HTML, Bash, JSON
• GitHub Flavored Markdown — tables, task lists, front matter, code blocks
• Recent files history
• Light & dark mode with preference saved

Editing

• In-browser editor — edit any file directly, save with ⌘S
• Create new files — add .md files to your folder from the sidebar
• Delete files — remove files with a confirmation prompt
• Find & Replace — ⌘F to search and replace within the editor
• Export to PDF — clean, print-ready output via the browser’s print dialog

Customisation

• Resizable sidebar, adjustable font size, reading width, font family
• 100% offline — no data ever leaves your machine

Installation

From Chrome Web Store

Install Markdown Browser

Load unpacked (development)

1. Clone or download this repository
2. Open icons/generate-icons.html in Chrome → click Download All → place the 4 PNGs in icons/
3. Go to chrome://extensions
4. Enable Developer mode (top-right toggle)
5. Click Load unpacked → select this folder
6. Click the extension icon in your toolbar

Usage

1. Click the Markdown Browser icon in the Chrome toolbar
2. In the sidebar, click Open Folder and select a local directory
3. Click any .md file to open it
4. Press ⌘K to search across all files
5. Click Edit in the file breadcrumb to edit the file directly

Keyboard Shortcuts

Shortcut	Action
⌘K	Open command palette / search
⌘[	Previous file
⌘]	Next file
⌘⇧F	Full-text search
⌘E	Enter / exit edit mode
⌘S	Save file (edit mode)
⌘F	Find & replace (edit mode)
ESC	Close palette, settings, or find bar

Supported File Types

.md · .mdx · .markdown · .mdown · .mkd · .txt

Privacy

This extension operates entirely offline. Read and write access to your files is granted only through Chrome’s built-in permission dialog at your explicit request. No data is collected or transmitted. See the Privacy Policy for the full policy.

Development

Pure vanilla JS — no build step, no dependencies, no bundler.

markdown-browser/
├── manifest.json        MV3 manifest (v2.0.0)
├── background.js        Service worker (opens app tab)
├── app.html             Main single-page app
├── app.js               App logic
├── app.css              Anthropic-inspired dark/light theme
├── lib/
│   ├── markdown.js      Custom GFM parser
│   └── highlighter.js   Syntax highlighter
├── about.html           About page
├── privacy.html         Privacy policy
└── icons/               Extension icons (PNG)

Changelog

v2.0.0

• In-browser markdown editor with ⌘S save
• Create new files from the sidebar
• Delete files with confirmation
• Find & Replace (⌘F) in editor
• Export to PDF with clean print output
• Persistent search bar in the header
• Visible Edit / PDF buttons in the file breadcrumb

v1.0.0

• Initial release: read-only markdown viewer, hot reload, full-text search, TOC, syntax highlighting

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Story behind the Tool

Since the dawn of the claude code and codex, I have been working with only markdown files. All of my research, planning, working is in markdowns. I needed something to quickly view my markdown repo, search, edit etc. VS code is good but still have to preview the file, I needed something offline and quick. There are some extensions online but they were paid. So I built one. now its one of the always open tab on my chrome. Hope this helps some markdown guy too. If it does, dont forget to give a shoutout to me on Twitter :P

abhikuchbhi.in

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License

MIT — see LICENSE

Author

abhikuchbhi.in

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