Complete guide to GitHub Flavored Markdown (GFM) syntax — including alerts, Mermaid diagrams, and LaTeX math that older cheat sheets skip
GitHub Flavored Markdown extends standard Markdown with extra features. See our Markdown Cheat Sheet for basic syntax.
Interactive checkboxes
- [x] Completed task - [ ] Incomplete task
URLs become links automatically
https://github.com is auto-linked
Link to issues and PRs
#123 or user/repo#123
Mention and notify users
@username
Link to commits
a1b2c3d4 or user/repo@a1b2c3d4
Emoji shortcodes
:+1: :sparkles: :rocket:
Simple table
| Header 1 | Header 2 | |----------|----------| | Cell 1 | Cell 2 |
Column alignment
| Left | Center | Right | |:-----|:------:|------:| | L | C | R |
Specify language for highlighting
```javascript const x = 1; ```
Show code changes
```diff - removed line + added line ```
Create diagrams
```mermaid graph TD; A-->B; ```
Informational callout
> [!NOTE] > Information note
Tip callout
> [!TIP] > Helpful tip
Important callout
> [!IMPORTANT] > Key information
Warning callout
> [!WARNING] > Warning message
Caution callout
> [!CAUTION] > Dangerous action
Add footnotes
Text with footnote[^1] [^1]: Footnote content
Collapsible content
<details> <summary>Click to expand</summary> Hidden content </details>
Keyboard key styling
<kbd>Ctrl</kbd> + <kbd>C</kbd>
Subscript text
H<sub>2</sub>O
Superscript text
X<sup>2</sup>
LaTeX math rendering
Inline $x^2$ or block:
$$
\sqrt{a^2 + b^2}
$$GitHub supports syntax highlighting for 100+ languages. Common ones include:
javascripttypescriptpythonrubygorustjavaccppcsharpphpswiftkotlinbashsqljsonyamlmarkdownhtmlcssPrefer a picture? Save or share the GitHub Markdown cheat sheet as a single image — handy for pinning in team chats, wikis, and study notes.
Download image (PNG)GitHub Flavored Markdown (GFM) is a superset of standard Markdown. It adds tables, task lists, strikethrough, autolinks, footnotes, syntax-highlighted code blocks, and GitHub-specific features like @mentions, issue references, alerts, Mermaid diagrams, and LaTeX math.
Use alerts: start a blockquote with [!NOTE], [!TIP], [!IMPORTANT], [!WARNING], or [!CAUTION] on its own line, for example "> [!WARNING]" followed by "> your message". GitHub renders it as a colored callout box in READMEs, issues, and PRs.
Yes. Create a fenced code block with the language set to mermaid and GitHub renders the diagram directly in READMEs, issues, discussions, and wikis — flowcharts, sequence diagrams, Gantt charts, and more.
Yes. Wrap inline expressions in single dollar signs ($x^2$) and display equations in double dollar signs. GitHub renders them with MathJax in Markdown files, issues, discussions, and PRs.
Use the HTML details element: <details><summary>Title</summary> your content </details>. Readers click the title to expand it. Leave a blank line after the summary tag so Markdown inside still renders.
Check for a separator row of dashes under the header row (| --- | --- |), make sure every row has the same number of pipes, and leave a blank line before the table. Pipes inside cells must be escaped with a backslash.
