Markdown Previewer

Write Markdown on the left and see the rendered HTML on the right. Supports GitHub Flavored Markdown (tables, task lists, fenced code).

About Markdown

Markdown is a lightweight plain-text formatting syntax created by John Gruber in 2004. It lets you write structured documents (headings, lists, links, code, tables) using simple punctuation marks, then convert them to HTML for the web. It powers READMEs on GitHub, posts on Reddit and Stack Overflow, documentation sites, and most static blog generators.

What this tool supports

The previewer renders GitHub Flavored Markdown (GFM), a popular CommonMark superset. You can use:

  • Headings (# through ######), paragraphs, and horizontal rules
  • Bold (**text**), italics (*text*), strikethrough (~~text~~), and inline code
  • Ordered and unordered lists, plus task lists (- [ ] and - [x])
  • Blockquotes, fenced code blocks with language tags, and pipe-syntax tables
  • Links, images, and autolinks

How it works

As you type, your Markdown is parsed in the browser using the open-source marked library, then run through DOMPurify before being inserted into the preview pane. Sanitization removes <script> tags, event handlers, and javascript: URLs, so pasting untrusted Markdown will not execute code in your browser.

Privacy

Everything happens locally. The libraries are fetched once from a public CDN, then your text is parsed and rendered entirely on-device. Nothing you type is uploaded, logged, or sent to a server, so you can safely preview private notes, internal docs, or unpublished posts.

Frequently asked questions

Which Markdown flavor does this tool render?
It renders GitHub Flavored Markdown (GFM), which is CommonMark plus tables, task lists, autolinks, and strikethrough. The result closely matches what you would see in a GitHub README.
Can I copy or download the rendered HTML?
Yes. Use the Copy HTML button to grab the generated HTML for pasting into a CMS or email, or use Download to save a standalone .html file you can open in any browser.
Is it safe to paste Markdown from an untrusted source?
The output is run through DOMPurify before being shown, which strips <script> tags, inline event handlers, and javascript: URLs. The preview is rendered inside a shadow DOM, so styles from the rendered content cannot leak into the rest of the page.
Does the tool work offline?
The first load fetches the parser and sanitizer from a public CDN. Once cached by the browser, the tool runs entirely offline. No request is made for the Markdown text itself, so your content stays on your device.