Markdown Syntax: The Complete Guide for Developers

Why Markdown?

Markdown is a lightweight markup language designed to be readable as plain text and convertible to HTML. Created by John Gruber in 2004, it became the standard for README files, documentation, blog posts, and note-taking apps. GitHub, GitLab, Notion, Obsidian, and hundreds of other tools render it natively.

Headings

# H1 — Page title
## H2 — Section
### H3 — Subsection
#### H4 — Sub-subsection

Emphasis

**bold** or __bold__
*italic* or _italic_
***bold italic***
~~strikethrough~~   (GFM extension)
==highlight==       (some parsers)

Lists

- Unordered item
- Another item
  - Nested item (2-space indent)

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

- [ ] Unchecked task (GFM)
- [x] Checked task (GFM)

Links and Images

[Link text](https://example.com)
[Link with title](https://example.com "Tooltip text")
[Reference link][ref]
[ref]: https://example.com

![Alt text](image.png)
![Alt text](image.png "Image title")

<https://example.com>   ← autolink

Code

Inline: Use backtick-code-backtick in a sentence.

Fenced code block (specify language for syntax highlighting):
triple-backtick javascript
const x = 1;
triple-backtick

Indented code block (4 spaces):
    const x = 1;

Tables (GFM)

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

Colons in the separator row control alignment: no colon = left, colon on right = right, colons on both = center.

Blockquotes

> This is a blockquote.
> It can span multiple lines.
>
> And multiple paragraphs.
>> Nested blockquote.

Horizontal Rules

---
***
___

Escaping

\*not italic\*     ← backslash escapes Markdown characters
\# not a heading

GitHub Flavored Markdown (GFM) Extras

• Task lists: - [x] done
• Strikethrough: ~~text~~
• Autolinks: bare URLs are clickable
• Footnotes: text[^1] + [^1]: footnote
• Alerts: > [!NOTE], > [!WARNING], etc.

Preview Markdown Instantly

Use ToolsVito's Markdown Preview to write Markdown and see a live rendered preview side by side — with GFM support.