Chrome Extension

May 26, 2026 · View on GitHub

The Chrome extension is the primary platform for Markdown Viewer, offering the most complete feature set.

Overview

FeatureStatus
Markdown rendering✅
Word export✅
All diagram types✅
LaTeX formulas✅
29 themes✅
Smart caching✅
Offline mode✅

Version: 5.0.0
Manifest: V3 (latest Chrome standard)

Installation

  1. Visit Chrome Web Store - Markdown Viewer
  2. Click "Add to Chrome"
  3. Confirm the installation

Manual Installation (For Developers)

  1. Clone the repository
  2. Run npm install && npm run build:chrome
  3. Open chrome://extensions/
  4. Enable "Developer mode"
  5. Click "Load unpacked"
  6. Select the chrome/dist folder

Permissions Explained

The extension requests these permissions:

PermissionPurpose
storageSave settings and cache locally
unlimitedStorageStore diagram cache without limits
offscreenRender diagrams in background
scriptingInject rendering scripts into pages
downloadsSave exported Word documents
file:///*Access local Markdown files
https://*/*, http://*/*Access online Markdown files

All data stays local. No information is sent to any server.

Supported File Types

The Chrome build uses the shared format registry from the core codebase:

ExtensionsType
.md, .markdown, .slides.mdMarkdown / Slidev documents
.plantuml, .pumlPlantUML diagrams
.mermaid, .mmdMermaid diagrams
.vega, .vl, .vega-liteVega / Vega-Lite charts
.gv, .dotGraphviz DOT graphs
.infographicInfographic charts
.canvasCanvas diagrams
.drawiodraw.io diagrams

Features

Automatic Rendering

When you open a supported file:

  1. The extension detects the file type
  2. Renders the content with syntax highlighting
  3. Processes any diagrams or formulas
  4. Displays the formatted result

Export to Word

  1. Click the Download button or press Ctrl/Cmd + S
  2. Watch the progress indicator
  3. Word document downloads automatically

Theme Selection

  1. Click the extension icon or theme button
  2. Browse 29 themes
  3. Click to apply instantly

Smart Caching

  • Diagrams are cached locally
  • First load: ~5 seconds (for complex docs)
  • Subsequent loads: <1 second

Settings

Access settings through:

  • Extension popup (click extension icon)
  • Right-click menu on extension icon

Available Settings

SettingDefaultOptions
Default themeDefaultAny of 29 themes
Cache size1000 items100-5000
Auto-detect URLsEnabledOn/Off

Keyboard Shortcuts

ActionShortcut
Export to WordCtrl/Cmd + S
Toggle TOCCtrl/Cmd + B
Zoom inCtrl/Cmd + +
Zoom outCtrl/Cmd + -
Reset zoomCtrl/Cmd + 0

Browser Compatibility

BrowserSupport
Google Chrome✅ Full support (88+)
Microsoft Edge✅ Full support
Brave✅ Full support
Opera✅ Full support
Vivaldi✅ Full support
Arc✅ Full support

Any Chromium-based browser should work.

Troubleshooting

Extension Not Working?

  1. Check if enabled: Go to chrome://extensions/ and verify it's turned on
  2. File access: For local files, enable "Allow access to file URLs"
  3. Restart browser: Try closing and reopening Chrome
  4. Reinstall: Remove and reinstall the extension

Diagrams Not Rendering?

  1. Wait for completion: Complex diagrams take time
  2. Check syntax: Verify your PlantUML/Mermaid/DOT/Vega syntax
  3. Clear cache: Try clearing the diagram cache in settings

Export Fails?

  1. Check permissions: Ensure download permission is granted
  2. Disk space: Verify you have disk space available
  3. Try again: Some complex exports may need a second attempt

Privacy & Security

  • ✅ Manifest V3 compliant (latest Chrome security standard)
  • ✅ All processing local
  • ✅ No external requests
  • ✅ No tracking or analytics
  • ✅ Open source and auditable

Updates

The extension updates automatically through Chrome Web Store. To check your version:

  1. Go to chrome://extensions/
  2. Find Markdown Viewer
  3. Version shown under the name

Source Code

GitHub: markdown-viewer-extension

The chrome/ directory contains all Chrome-specific code.