Markdown Guard Preview

Fast, secure Markdown preview for VS Code with Mermaid diagrams, KaTeX math, HTML/PDF export and diagnostics.

Markdown Guard Preview is built as a safer, simpler alternative to heavyweight Markdown preview extensions. It focuses on predictable rendering, strict webview security, clear errors and professional export workflows.

Features

• Secure Markdown preview for VS Code
• Mermaid Markdown preview with inline error reporting
• KaTeX math rendering for inline and block formulas
• Export Markdown to HTML
• Export Markdown to PDF through Chrome-compatible browsers
• Markdown Guard: Doctor diagnostics command
• VS Code theme-aware preview
• Raw HTML disabled by default
• No code chunk execution in the MVP
• No arbitrary workspace JavaScript execution
• Strict Content Security Policy for the preview webview

Why This Exists

Many Markdown preview tools are powerful but difficult to operate safely. Markdown Guard Preview starts from the opposite direction:

• Security first
• Fast by default
• Small configuration surface
• Clear diagnostics
• Export reliability before feature sprawl

Commands

• Markdown Guard: Open Secure Preview
• Markdown Guard: Export HTML
• Markdown Guard: Export PDF
• Markdown Guard: Doctor

Markdown Preview Enhanced Alternative

Markdown Guard Preview is designed for users who want a modern Markdown Preview Enhanced alternative with a stricter security model, clearer diagnostics and a focused export pipeline.

Settings

• markdownGuard.liveUpdate
• markdownGuard.liveUpdateDebounceMs
• markdownGuard.allowHtml
• markdownGuard.enableMermaid
• markdownGuard.enableKatex
• markdownGuard.mermaidTheme
• markdownGuard.pdfWaitMs
• markdownGuard.maxFileSizeBytes

Roadmap

• PlantUML local rendering
• D2 local rendering
• GraphViz local rendering
• Pandoc export
• Word export
• Wiki links and backlinks
• Graph view
• VS Code Web support
• Workspace trust profiles

Security

Markdown Guard Preview intentionally avoids dangerous capabilities in the MVP. It does not execute code chunks, does not evaluate workspace JavaScript and does not inject arbitrary workspace HTML into the webview head.

If you find a security issue, please report it privately through GitHub Security Advisories once the repository is public.