Offline Markdown Preview installs statistics

Offline Markdown Preview

Offline Markdown preview for VS Code with Mermaid diagrams, KaTeX math, secure local rendering, export, scroll sync, and outline navigation.

Offline + Secure: runs locally inside VS Code and the extension does not send your Markdown contents anywhere (no cloud, no telemetry).

GIF Demos

A quick tour of key workflows (all offline, inside VS Code):

<table> <tr> <td width="50%" valign="top"> <strong>Live preview + scroll sync</strong><br/> <img src="https://github.com/Bowlerr/offline-markdown-preview/raw/HEAD/images/scroll.gif" alt="Live preview and scroll sync demo" /> </td> <td width="50%" valign="top"> <strong>Mermaid + math rendering</strong><br/> <img src="https://github.com/Bowlerr/offline-markdown-preview/raw/HEAD/images/mermaid.gif" alt="Mermaid and math rendering demo" /> </td> </tr> <tr> <td width="50%" valign="top"> <strong>Outline + heading navigation</strong><br/> <img src="https://github.com/Bowlerr/offline-markdown-preview/raw/HEAD/images/content-scroll.gif" alt="Outline and heading navigation demo" /> </td> <td width="50%" valign="top"> <strong>Remote image download + cache</strong><br/> <img src="https://github.com/Bowlerr/offline-markdown-preview/raw/HEAD/images/remote-images.gif" alt="Remote image download and cache demo" /> </td> </tr> </table>

What You Get

• Free: no paywalls; MIT-licensed.
• Offline + secure by design: render/preview/export works locally with bundled libraries (no CDN, no remote fonts, no telemetry).
• Secure webview defaults: strict CSP + HTML sanitization (DOMPurify) enabled by default.
• Markdown preview panel with live updates and editor/preview scroll sync.
• Bundled rendering stack: Mermaid diagrams, KaTeX math, Prism syntax highlighting.
• Navigation tools: Markdown outline TreeView, heading quick pick, copy heading links.
• Export tools: HTML export and PDF export from the preview workflow.
• Safety controls: external-link confirmation, image size limits, sanitization toggle (with explicit unsafe wording).

Quick Start

1. Open a Markdown file (.md) in VS Code.
2. Preview opens automatically by default (offlineMarkdownViewer.preview.autoOpen = true) when a Markdown editor becomes active.
3. You can also run Offline Markdown Preview: Open Preview (or Open Preview in Current Group) manually.
4. Use the outline view and heading commands to navigate larger documents.
5. Export when needed with Export HTML or Export PDF.

Tip: use the editor title action to open preview while editing.

Privacy, Offline, and Data Safety

• No network required for render, preview, or export.
• No telemetry and no document-content upload.
• Remote web requests are blocked in the webview runtime (fetch, XMLHttpRequest, WebSocket, EventSource) for http(s) targets.
• Remote images are blocked by default; you can opt in via offlineMarkdownViewer.preview.allowRemoteImages.
• When remote images are blocked, each remote image gets a Download Image action that caches it locally and replaces it in preview.
• Strict CSP includes connect-src 'none'.
• Sanitization is on by default (offlineMarkdownViewer.sanitizeHtml = true).
• Export writes files only on explicit user action (HTML/PDF commands).

Settings

These VS Code settings control rendering, safety, and performance:…