Markdown is a lightweight markup language that uses plain-text syntax to indicate formatting. It was created by John Gruber in 2004 and is now widely used in README files, documentation, blogging platforms, and comment systems.

Which Markdown flavours are supported?

This tool supports CommonMark plus GitHub-Flavored Markdown (GFM) extensions including tables, strikethrough (~~text~~), and task list checkboxes (- [ ] item).

How quickly does the preview update?

The preview re-renders after every change you make. Each conversion runs in a background worker and is stopped after 2 seconds, a limit ordinary documents never come near; long runs of unmatched _ or * characters are the usual cause of a stopped preview.

How do I switch between the editor and the preview on a phone?

On screens 640 pixels wide or narrower, the editor and the preview share one pane: tap Write to edit and Preview to see the result. Copy HTML sits next to the two buttons.

Live Markdown preview

See your Markdown rendered as HTML in real time as you type. The preview updates with every keystroke. Use the split view on desktop or the tab switcher on mobile.

MARKDOWN301 chars

PREVIEW

Preview renders in a sandboxed iframe. No scripts execute, and raw HTML is reduced to basic formatting: links show their address on hover and only embedded (data:) images display. Converted with marked in a background worker, which stops after 2 seconds.

How it works

The tool uses marked, a fast, CommonMark-compliant Markdown parser, running in a background Web Worker in your browser. As you type, marked converts the Markdown syntax to HTML which is rendered in a live preview pane. A conversion that takes longer than 2 seconds is stopped and a message shown instead.

Processing runs in your browser

All parsing and rendering happens locally in your browser tab. Our servers are not involved at any point.

Related operations

For escaping reserved HTML characters in your Markdown, try HTML entities. To count the words you have drafted, use the word counter. For bulk edits to recurring phrases, see find and replace.

Frequently asked questions

What is Markdown?: Markdown is a lightweight markup language that uses plain-text syntax to indicate formatting. It was created by John Gruber in 2004 and is now widely used in README files, documentation, blogging platforms, and comment systems.
Which Markdown flavours are supported?: This tool supports CommonMark plus GitHub-Flavored Markdown (GFM) extensions including tables, strikethrough (~~text~~), and task list checkboxes (- [ ] item).
How quickly does the preview update?: The preview re-renders after every change you make. Each conversion runs in a background worker and is stopped after 2 seconds, a limit ordinary documents never come near; long runs of unmatched _ or * characters are the usual cause of a stopped preview.
How do I switch between the editor and the preview on a phone?: On screens 640 pixels wide or narrower, the editor and the preview share one pane: tap Write to edit and Preview to see the result. Copy HTML sits next to the two buttons.

Last reviewed September 30, 2026

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