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Markdown Studio — Live Editor & Preview

A split-view Markdown editor with instant GFM preview, a table formatter that aligns pipes, an automatic table of contents and HTML export. Output is always sanitized and external images load only when you allow them.

On-device・No upload

Your files and input are processed only inside your browser on this device and are never uploaded to our servers.

Markdown
Lines: 0
Preview
Type Markdown and the preview appears here

How to use

  1. Type in the Markdown pane or open a .md file. The preview updates as you type.

  2. Use the toolbar (headings, bold, lists, links, tables…) or Ctrl / ⌘ + B, I, K. Commands apply to the selection and toggle off when pressed again.

  3. After writing a table, press “Format tables” to align its pipes; wide characters such as CJK count as two columns.

  4. Open “Table of contents” to jump to any heading in the preview, or insert a Markdown TOC at the top.

  5. Export with “Copy HTML”, “Save .md” or “Save HTML file” (a single file with embedded CSS that opens in any browser).

What it does

Live GFM preview

Tables, task lists, strikethrough, fenced code and autolinks (powered by marked). Switch between split, editor-only and preview-only views; split view keeps scrolling in sync.

Always-sanitized output

Rendered HTML always passes through DOMPurify: scripts, event handlers, iframes and media that load remote content are removed. Links open in a new tab with rel="noopener noreferrer".

External images are opt-in

Remote images are replaced by a placeholder until you allow them, so opening a document cannot ping tracking pixels. Turn on “Load external images” when you need them.

Table formatter with wide-character support

Aligns the pipes of every GFM table and keeps left/center/right alignment markers. CJK characters and emoji count as two columns, and code fences are left untouched.

Toolbar and shortcuts

Headings, bold, italic, strikethrough, code, lists, task lists, quotes, links, images, code blocks, tables and rules — with the browser’s own undo (Ctrl+Z) still working.

TOC and export

Builds a linked table of contents (with Unicode-friendly slugs), and exports HTML to the clipboard, a .md file, or a standalone HTML document with embedded CSS.

Use cases

  • Draft a GitHub README, issue or pull-request description and check how it renders
  • Fix a Markdown table whose columns no longer line up
  • Turn Markdown notes into HTML for e-mail or a CMS
  • Generate a table of contents for a long document
  • Edit confidential notes without uploading them anywhere

Supported formats

Open

.md.markdown.txt (UTF-8)

Export

Markdown (.md)HTML (clipboard)Standalone HTML file (embedded CSS)

Capability matrix

FeatureSupportNotes
GitHub Flavored Markdown (tables, task lists, strikethrough)Supported—
HTML sanitization (scripts, event handlers removed)SupportedAlways on
External imagesPartialBlocked by default; loaded only when you switch them on
Table formatting with wide charactersSupported—
Math (LaTeX) and Mermaid diagramsNot supported—
Syntax highlighting in code blocksNot supportedCode is shown in monospace
HTML → Markdown conversionNot supported—
PDF / Word exportNot supportedOpen the HTML file and print to PDF from your browser
Offline useSupportedWorks without a connection once loaded (except external images)

Limits & notes

  • Files up to 5 MB.
  • Raw HTML is limited to safe elements; script, style, iframe, form, video and similar tags are removed.
  • Allowing external images sends your IP address and browser details to the image hosts.
  • Scroll sync matches relative position, so documents with many images or tables can drift slightly.

Privacy & safety

Your Markdown is converted inside your browser and never sent to or stored on LIBRA Works servers. External images are not fetched until you allow them, so opening a document triggers no third-party requests.

FAQ

Will it look the same as on GitHub?
Structurally almost always: it follows GitHub Flavored Markdown (tables, task lists, strikethrough, autolinks). Emoji shortcodes like :smile:, math, Mermaid diagrams and syntax colors are not supported.
How do I align a Markdown table?
Press “Format tables”. Column widths are measured (wide CJK characters count as two) and the pipes are lined up, keeping any alignment markers like :---:.
Does <script> in Markdown run?
No. The preview and exported HTML are sanitized by DOMPurify, which removes scripts and event attributes such as onerror. Exported HTML files also include a Content Security Policy that blocks scripts.
Why are my images shown as placeholders?
For privacy, images from the internet are not loaded by default. Turn on “Load external images” to show them.
How do I convert Markdown to HTML?
Use “Copy HTML” for the body HTML, or “Save HTML file” for a complete document with embedded styles that you can open, share or print to PDF.
Is my text saved or uploaded?
No. Everything happens in your browser and nothing is uploaded. Closing the page discards your text, so use “Save .md” to keep it.

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