Advanced Markdown Previewer
Professional Markdown editor with live preview, syntax highlighting, math rendering, and comprehensive statistics
Examples
Render strong emphasis
**bold**<p><strong>bold</strong></p>Two asterisks on each side become a strong element inside a paragraph.
Render an ATX heading
# Release Notes<h1>Release Notes</h1>One leading hash followed by a space produces a level-one heading.
Render an unordered list
- alpha
- beta<ul>
<li>alpha</li>
<li>beta</li>
</ul>Adjacent dash-prefixed items form one unordered list with two list items.
About this tool
The Advanced Markdown Previewer renders Markdown with react-markdown and updates the preview as the source changes. It supports side-by-side, edit-only, and preview-only views, plus GitHub Flavored Markdown through remark-gfm and mathematical notation through remark-math and KaTeX.
Rendering options independently enable GFM, math, raw HTML parsing, syntax highlighting, and external-link handling. Raw HTML is processed with rehype-raw and then sanitized with rehype-sanitize; fenced code can be highlighted with rehype-highlight, and enabled external links open in a new tab with nofollow, noopener, and noreferrer relationships.
You can load .md, .markdown, or .txt files, save the Markdown source, copy it, or download the component's styled HTML document shell. The statistics panels count characters, words, lines, headings, links, images, code blocks, tables, list items, and blockquotes, and estimate reading time at 200 words per minute.
How to use
Enter or load Markdown
Type in the editor, select a complete guide, technical documentation, or math sample, or load a .md, .markdown, or .txt file.
Choose the workspace view
Use Side by Side for live editing, Edit Only for a larger source area, or Preview Only for the rendered document.
Configure rendering
Toggle GFM, KaTeX math, raw HTML parsing, syntax highlighting, and external-link handling to match the destination where the Markdown will be rendered.
Inspect and save
Review the rendered result and document statistics, then copy the Markdown or save the source as a .md file.
Use cases
Drafting README and documentation files
Edit Markdown beside its rendered form to catch heading, list, link, table, and code-block issues before committing documentation.
Checking GitHub Flavored Markdown
Preview GFM tables, task lists, strikethrough, and autolinks with the same extension family commonly used for repository content.
Reviewing technical and mathematical content
Render fenced code with highlighting and inspect inline or block math through remark-math and KaTeX.
Estimating document size and reading time
Use word, character, line, element, and reading-time statistics while shaping release notes, guides, or API documentation.
Common mistakes
Mistake:Assuming every Markdown renderer supports the same GFM extensions as CommonMark.
Fix:CommonMark defines the core syntax; GFM adds features such as tables, task lists, strikethrough, and extended autolinks. Match the previewer's GFM toggle to the destination renderer.
Mistake:Indenting nested list items by eye instead of relative to the parent marker.
Fix:Indent continuation content and child lists far enough to belong to the parent item. When nesting is ambiguous, use consistent spacing and verify the resulting list structure in the preview.
Mistake:Expecting enabled raw HTML to bypass safety filtering.
Fix:The preview parses raw HTML only when enabled, then always runs rehype-sanitize. Unsupported or unsafe elements and attributes may be removed; use Markdown constructs whenever possible.
Mistake:Writing literal asterisks or underscores without escaping them.
Fix:Prefix punctuation with a backslash, such as `\*literal\*`, when it should appear as text rather than emphasis. Use code spans for literal syntax fragments.
Frequently asked questions
Related guides
References & standards
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