Markdown Alerts
Last updated: 2026-10-14
Alerts GitHub feature
A GitHub extension. Writing > [!NOTE] and four sibling markers inside a quote turns it into an icon-colored callout: NOTE blue, TIP green, IMPORTANT purple, WARNING yellow, CAUTION red.
| Group | GFM Extensions |
|---|---|
| Spec level | GitHub feature |
| Spec version | CommonMark 0.31.2 + GFM |
📝 Syntax
> [!NOTE]
> note content▶ Live Example
Edit Markdown on the left, see the result on the right
💡 Key points
⚠️ Warning GitHub-specific: other renderers usually show it as a plain blockquote (no error, no style).
ℹ️ Note This site's tutorials render callouts from structured notes; alerts are GitHub-page syntax.
❓ FAQ
Q Which five types exist?
A [!NOTE], [!TIP], [!IMPORTANT], [!WARNING], [!CAUTION] — escalating severity.
Q Is the marker case-sensitive?
A Yes — uppercase required, on the first line of the quote.
Q Can alerts nest other elements?
A Yes — lists, fences and links inside the quote all work.
📚 See also
BlockquotesCommonMark core EmojiGitHub feature