This FAQ answers common questions about using, deploying, and troubleshooting Markdown Viewer (v3.7.4).
Markdown Viewer is a client-side Markdown editing suite and live preview tool. It features off-thread Web Worker parsing, incremental DOM patching, responsive split views, interactive diagrams (Mermaid), and mathematical equation formatting (LaTeX).
Yes. It is free and open-source software licensed under the Apache License 2.0.
No. The application is serverless and does not require registration, login, or subscription.
No. All parsing, rendering, typesetting, and exporting happen entirely on your computer inside the browser. No document text or metadata is uploaded to external servers.
No. The application does not contain tracking scripts, telemetry code, cookies, or advertising pixels.
The app saves your settings (theme, view mode, scroll synchronization state) and open tab documents to your browser's local storage (localStorage). This enables auto-saving and restores your workspace when you reload the page.
You can clear this data by using your browser's site settings or developer tools:
F12).Yes. It uses the marked.js library to support standard GFM features, including tables, task checklists, strikethrough, autolinks, and emoji shortcodes.
Yes. The application uses MathJax to format equations. You can write inline equations using single dollar signs ($E=mc^2$) or block equations using double dollar signs ($$...$$). For more details, see the Markdown Reference page.
Yes. You can write diagrams using Mermaid syntax inside fenced code blocks marked with mermaid. The preview pane displays these as interactive SVG diagrams. Double-click any diagram in the preview to open a zoomable, draggable modal.
Exporting to PDF uses html2canvas and jsPDF to capture screenshots of the preview pane page-by-page. While the app uses a sandboxing and pagination engine to adjust page breaks and scale elements, some complex CSS layouts, font styles, or wide code blocks may not render perfectly.
[!TIP] For the highest PDF quality, use your browser's built-in print command (
Ctrl + PorCmd + P) and select "Save as PDF".
index.html, and rebuild the application.Copy the static assets (index.html, script.js, preview-worker.js, styles.css, sw.js, and assets/) and serve them using a static web server (such as Nginx, Apache, or Caddy).
[!WARNING] Do not open the
index.htmlfile directly using thefile://protocol in your browser. Security policies (CORS) block Web Workers from running from local files, which will break the preview parser.
F12) to check for scripts blocked by security policies or network errors.Ctrl + Shift + R or Cmd + Shift + R) to clear cached script instances.MathJax loads dynamically when math markers are detected in your document. Ensure you have an active internet connection to download the library on first use, and check that your LaTeX syntax is correct.
Check that:
mermaid.macOS blocks unsigned binaries by default. To run the app, clear the quarantine flag using your terminal:
xattr -d com.apple.quarantine markdown-viewer-mac_universal
chmod +x markdown-viewer-mac_universal
You can also right-click the binary in Finder, click Open, and confirm the launch prompt.