Does this exactly match GitHub's rendering?

It follows the same specifications, CommonMark plus GitHub-Flavored Markdown, but marked is a different parser from GitHub's, so small differences are possible. GitHub-only additions stay as typed: an alert such as > [!NOTE] shows as a plain blockquote, and emoji shortcodes, @mentions and math are not converted. Footnotes are not supported either: a [^1] marker and its [^1]: note line stay as plain text, except when the note is a single word or URL, which marked reads as a link, so the marker becomes a link labelled ^1 and the note line disappears. The preview also uses this site's styles rather than GitHub's.

Which GitHub-Flavored Markdown features work?

Tables, fenced code blocks with language hints, task list checkboxes (- [ ] / - [x]), strikethrough (~~text~~), and bare URLs turned into links all render. In the preview, links show their URL as a tooltip and cannot be followed, and images from web addresses, such as README badges, do not display; only images embedded as data: URLs do.

Can I draft a README before pushing it?

Yes. Paste your README content and review it locally before committing. This is a fast way to catch broken tables, missing headings, or incorrect code-block fences.

Is my Markdown sent to a server?

All rendering runs in your browser using the marked library. Our servers are not involved at any point.

GitHub Markdown Preview

Preview a README, issue comment, or pull request body with CommonMark plus GitHub-Flavored Markdown, the same specifications GitHub follows, so tables, task lists, and fenced code blocks come out with the structure you expect. All rendering runs in your browser using the marked library.

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

Does this exactly match GitHub's rendering?: It follows the same specifications, CommonMark plus GitHub-Flavored Markdown, but marked is a different parser from GitHub's, so small differences are possible. GitHub-only additions stay as typed: an alert such as > [!NOTE] shows as a plain blockquote, and emoji shortcodes, @mentions and math are not converted. Footnotes are not supported either: a [^1] marker and its [^1]: note line stay as plain text, except when the note is a single word or URL, which marked reads as a link, so the marker becomes a link labelled ^1 and the note line disappears. The preview also uses this site's styles rather than GitHub's.
Which GitHub-Flavored Markdown features work?: Tables, fenced code blocks with language hints, task list checkboxes (- [ ] / - [x]), strikethrough (~~text~~), and bare URLs turned into links all render. In the preview, links show their URL as a tooltip and cannot be followed, and images from web addresses, such as README badges, do not display; only images embedded as data: URLs do.
Can I draft a README before pushing it?: Yes. Paste your README content and review it locally before committing. This is a fast way to catch broken tables, missing headings, or incorrect code-block fences.
Is my Markdown sent to a server?: All rendering runs in your browser using the marked library. Our servers are not involved at any point.

Last reviewed September 30, 2026

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