How to create colored alert callout boxes in markdown using GitHub Alerts and Obsidian callout syntax. Note, warning, tip, and important.
Alerts (also called callouts or admonitions) are styled blockquotes that highlight important information with color and an icon. GitHub introduced a > [!NOTE] syntax in 2023. Obsidian uses > [!tip] syntax. Both extend standard blockquote syntax with a type keyword on the first line.
Renders with a blue ℹ️ icon on GitHub.
Renders with an orange ⚠️ icon on GitHub.
GitHub supports five alert types: NOTE (blue), TIP (green), IMPORTANT (purple), WARNING (orange), CAUTION (red).
Obsidian syntax allows a custom title after the type.
| Platform | Supported | Notes |
|---|---|---|
| GitHub | Yes | Five types: NOTE, TIP, IMPORTANT, WARNING, CAUTION |
| GitLab | No | Renders as plain blockquote |
| Obsidian | Yes | Rich callout system with many types |
| Discord | No | — |
| Notion | No | — |
| Slack | No | — |
> NOTE: text
> [!NOTE] > text
The [!TYPE] keyword must be on its own line immediately after the > — plain text won't render as an alert.
If everything is important, nothing is. Reserve IMPORTANT and WARNING alerts for genuinely critical information — overuse makes readers ignore them.
On platforms without alert support, the > [!NOTE] renders as a plain blockquote — content is still visible, just without the colored styling.
Everything you need to know.
On GitHub, use: > [!NOTE]\n> Your note text. This renders as a blue highlighted callout. On Obsidian, use > [!note] with an optional title.
Blockquotes in markdown start with a greater-than sign (>) followed by a space. They render as indented, visually distinct blocks — perfect for quoting text, highlighting notes, or calling out important information.
Collapsible sections in markdown use the HTML <details> and <summary> elements. The <summary> text is always visible and acts as the toggle — clicking it expands or collapses the hidden content inside <details>. This is widely supported on GitHub and GitLab for hiding long code samples, changelogs, or optional content.
Most markdown parsers allow you to embed raw HTML directly in your markdown file. HTML blocks let you use elements not supported by markdown — custom divs, details/summary, colored text, form elements, and more. HTML support depends on the platform — some sanitize or strip it entirely.
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