Markdown Cheat Sheet: Complete Syntax Reference with Examples

Markdown is the universal writing format for developers — README files, documentation, GitHub issues, pull request descriptions, and technical blogs all use it. The syntax is minimal by design: a few punctuation conventions translate to clean HTML. This reference covers standard CommonMark syntax plus the GitHub Flavored Markdown (GFM) extensions that most platforms support.

Headings

# H1 — Page title (use once per document)
## H2 — Major section
### H3 — Subsection
#### H4 — Sub-subsection
##### H5
###### H6

Always put a space between the # and the heading text. Leave a blank line before and after headings.

Emphasis

Lists

- Unordered item (use - or * or +)
- Second item
  - Nested item (indent 2 spaces)
    - Deeper nested

1. Ordered item
2. Second item
   1. Nested ordered
3. Third item

For consistent rendering, use - for unordered lists. Do not mix marker characters in the same list. Indent nested items by 2 spaces (CommonMark) or 4 spaces (some older parsers).

Task lists (GFM)

- [x] Completed task
- [ ] Incomplete task
- [ ] Another task

Links and images

[Link text](https://example.com)
[Link with title](https://example.com "Tooltip on hover")

![Alt text](image.png)
![Alt text](https://example.com/image.png "Optional title")

<!-- Reference-style links -->
[Link text][ref]
[ref]: https://example.com "Optional title"

Blockquotes

> This is a blockquote.
> It can span multiple lines.
>
> Separate paragraphs with a blank quoted line.
>
> > Nested blockquote.

Code blocks

```javascript
const greeting = "Hello, world!";
console.log(greeting);
```

```python
def greet(name):
    return f"Hello, {name}!"
```

```sql
SELECT id, name FROM users WHERE active = true;
```

Always specify the language identifier after the opening backticks — it enables syntax highlighting on GitHub, GitLab, and most documentation platforms.

Tables (GFM)

| Column 1 | Column 2 | Column 3 |
| -------- | :------: | -------: |
| Left     | Center   | Right    |
| aligned  | aligned  | aligned  |

The colon in the separator row controls alignment: :---- = left (default), :----: = center, ----: = right. Pipes at the start and end are optional but recommended for readability.

Horizontal rules

---

***

___

Three or more hyphens, asterisks, or underscores on their own line. Always surround with blank lines to avoid being parsed as an H2 underline.

Escaping

Backslash-escape any Markdown character to output it literally:

*not italic*
[not a link]
# not a heading

HTML in Markdown

Most parsers allow raw HTML inline. Use it sparingly for things Markdown cannot express — centered content, custom attributes, or subscript/superscript:

H<sub>2</sub>O and E = mc<sup>2</sup>

<details>
<summary>Click to expand</summary>

Collapsed content here.

</details>

Quick reference