About Markdown Preview
Markdown is a lightweight markup language created by John Gruber that lets you write formatted content using plain text syntax. It is used extensively on platforms like GitHub, GitLab, Stack Overflow, Reddit, Notion, and many static site generators (Jekyll, Hugo, Gatsby). This preview tool renders your Markdown to HTML in real time using the marked library, which supports CommonMark and GitHub Flavored Markdown (GFM) features. The rendered output is sanitized with DOMPurify to prevent XSS when pasting untrusted Markdown. Supported elements include headings (h1-h6), bold, italic, strikethrough, links, images, ordered and unordered lists, code blocks with syntax highlighting, blockquotes, horizontal rules, and tables. All parsing and rendering run entirely in your browser. For converting HTML to Markdown, see our HTML to Markdown converter, and for generating Markdown tables, try our Markdown Table Generator.
How to Use Markdown Preview
- Type or paste your Markdown content into the Markdown editor on the left.
- The Preview panel on the right updates in real time, showing how your Markdown renders as HTML.
- Use standard Markdown syntax:
#for headings,**bold**for bold,*italic*for italic,[text](url)for links, etc. - Review the preview to verify formatting, then copy your Markdown for use in your target platform.
Key Features
- Live real-time preview — See rendered HTML update instantly as you type Markdown.
- Full Markdown support — Headings, bold, italic, strikethrough, links, images, lists, code blocks, blockquotes, and tables.
- GFM compatibility — Supports GitHub Flavored Markdown extensions including tables and task lists.
- XSS protection — Rendered HTML is sanitized with DOMPurify to prevent script injection from untrusted input.
- Browser-based privacy — All rendering runs locally in your browser. Your content never leaves your device.
- No account needed — Start writing and previewing immediately without any signup.
When to Use This Tool
- Drafting README.md files for GitHub or GitLab repositories and checking the formatting.
- Writing documentation or blog posts in Markdown and verifying the rendered output.
- Learning Markdown syntax with instant visual feedback on how each element renders.
- Previewing Markdown content before pasting it into platforms like Notion, Jira, or Confluence.
- Quickly checking the rendering of Markdown snippets shared in code reviews or chat.
Technical Details
The tool uses the marked JavaScript library for Markdown parsing, which implements the CommonMark specification with extensions for GitHub Flavored Markdown (GFM). The Markdown is parsed to an HTML string, then passed through DOMPurify to strip potentially dangerous elements (script tags, event handlers, etc.) before being rendered in the preview panel. This sanitization step makes the tool safe for pasting untrusted Markdown from external sources. The preview updates on every keystroke using a debounced rendering function for smooth performance. Code blocks support basic syntax highlighting for common languages. The tool runs entirely client-side with no server communication.
Conclusion
Markdown Preview provides a fast, private, and intuitive way to write and preview Markdown with real-time rendering. Whether you're drafting documentation, writing blog posts, or learning Markdown syntax, this browser-based tool delivers instant visual feedback without any server dependency.