What is the difference between CommonMark and GitHub Flavored Markdown?

CommonMark specifies a tight core grammar for interoperability. GFM extends it with tables, task lists, strikethrough, autolinks, and fenced code language hints. Preview behavior depends on which flavor your renderer implements—match the tool to GitHub, GitLab, or your static site generator.

Do tables work everywhere in Markdown?

Pipe tables are a GFM feature; many parsers support them, but not all. Alignment rows (` :--- `) and escaping pipes inside cells vary. Always preview before publishing; for complex grids, HTML ` ` or generated docs from structured data may be more reliable.

Can I embed raw HTML in Markdown?

Most renderers pass through safe HTML tags when allowed, but sanitization strips scripts and event handlers on user-generated content. Documentation sites often allow a whitelist. Relying on HTML for layout reduces portability—use it for figures or spans when Markdown falls short, not as the default.

Which Markdown features confuse new authors?

Nested lists need consistent indentation; code fences need matching backtick counts; links with parentheses need careful bracket/paren pairing; emphasis can break mid-word in some parsers. Live preview catches these faster than CI failures on a README.

How do I diff or review Markdown changes?

Use version control for source; for rendered output, compare HTML exports or rely on platform previews. For parallel prose or spec text, a [text diff](/text-diff) on the `.md` source is usually enough—focus on headings and link targets in review.

Markdown Preview

v1.0.0

Write Markdown and see it rendered as HTML in real time. Supports GitHub Flavored Markdown including tables, task lists, and strikethrough.

Markdown

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Markdown

See Markdown render as you write and grab HTML when your publishing stack needs it—fewer surprises on GitHub or in static site builds.

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Frequently Asked Questions

What is the difference between CommonMark and GitHub Flavored Markdown?: CommonMark specifies a tight core grammar for interoperability. GFM extends it with tables, task lists, strikethrough, autolinks, and fenced code language hints. Preview behavior depends on which flavor your renderer implements—match the tool to GitHub, GitLab, or your static site generator.
Do tables work everywhere in Markdown?: Pipe tables are a GFM feature; many parsers support them, but not all. Alignment rows (` :--- `) and escaping pipes inside cells vary. Always preview before publishing; for complex grids, HTML `<table>` or generated docs from structured data may be more reliable.
Can I embed raw HTML in Markdown?: Most renderers pass through safe HTML tags when allowed, but sanitization strips scripts and event handlers on user-generated content. Documentation sites often allow a whitelist. Relying on HTML for layout reduces portability—use it for figures or spans when Markdown falls short, not as the default.
Which Markdown features confuse new authors?: Nested lists need consistent indentation; code fences need matching backtick counts; links with parentheses need careful bracket/paren pairing; emphasis can break mid-word in some parsers. Live preview catches these faster than CI failures on a README.
How do I diff or review Markdown changes?: Use version control for source; for rendered output, compare HTML exports or rely on platform previews. For parallel prose or spec text, a [text diff](/text-diff) on the `.md` source is usually enough—focus on headings and link targets in review.