Markdown Callout / Admonition Generator

Markdown Callout / Admonition Generator

A callout (also called an admonition) is a highlighted box used to call out a note, tip, or warning from the surrounding text. Markdown has no native syntax for this at all — every platform that supports callouts invented its own, incompatible syntax on top of Markdown. This tool generates correctly-formatted callout syntax for the platform you're actually targeting, so you don't have to remember which one uses > [!NOTE] versus !!! note versus :::note.

Syntax comparison

Type mapping isn't 1:1 across platforms

This tool uses GitHub's own five alert types — Note, Tip, Important, Warning, Caution — as the canonical set, since GitHub/GitLab define it precisely and it covers the common cases. Obsidian, MkDocs, and Docusaurus each have a different type vocabulary, so the mapping isn't always exact:

* Not an exact name match — the target platform has no type of that exact name, so the nearest equivalent by meaning was chosen. Obsidian and MkDocs both support a much larger type vocabulary than the five shown here (e.g. Obsidian also has success, question, bug, example, quote) — if you need one of those, generate the closest canonical type here and hand-edit the bracketed type name in the output.

Renderer support — be honest about it

None of this is universal, and getting the syntax right doesn't guarantee it renders as a styled box:

• GitHub renders > [!NOTE]-style alerts specially only on GitHub.com itself (READMEs, issues, PRs, wikis) — Jekyll/kramdown, Hugo, and plain CommonMark renderers will just show it as an ordinary blockquote with literal [!NOTE] text, since that's genuinely all it is outside GitHub's own renderer.
• GitLab supports the identical five-type alert syntax since GitLab 16.6, with the same GitHub-only caveat — it only renders specially inside GitLab itself.
• Obsidian callouts render natively in Obsidian's own editor and reading view, including live fold/unfold. Pasted into GitHub or elsewhere, only the lowercase types that happen to overlap with GitHub's own five (note, tip, warning) will render as alerts there too — GitHub matches type names case-insensitively but doesn't recognize Obsidian-only types like danger or info as valid alert types, and folded state is an Obsidian-only concept with no GitHub equivalent.
• MkDocs needs the admonition extension enabled in mkdocs.yml (markdown_extensions: [admonition]) — the syntax is inert plain text without it, and Material for MkDocs additionally supports a ???/ ???+ collapsible variant this tool doesn't generate.
• Docusaurus admonitions work out of the box in Docusaurus v2/v3's default MDX pipeline — no extra plugin needed — but the syntax is MDX-specific and won't render (or will break the build) in a plain .md file processed outside Docusaurus.

Test the output on your actual target platform before relying on it — this tool gets the syntax right, but it can't guarantee your specific renderer/plugin configuration recognizes it.

Common use cases

• READMEs — flag prerequisites, gotchas, or breaking changes so they can't be missed while skimming
• Documentation sites — MkDocs and Docusaurus docs use admonitions constantly for tips and warnings
• PR and issue templates — call out required steps or known limitations
• Tutorials — separate "by the way" notes and "don't do this" warnings from the main instructions

For a deeper walkthrough of callout syntax across platforms, see our companion guide: Markdown Admonitions and Callouts: The Complete Guide.

Related tools

• Markdown Live Editor — write and preview your full document, callouts included
• Markdown Linter — check the rest of your document for style issues
• Collapsible Section Generator — another correctly-formatted-special-syntax generator, for <details> blocks