Markdown is a lightweight markup language created by John Gruber in 2004. It allows you to write formatted text using plain-text syntax that is easy to read and write. Markdown is widely used for documentation, README files, blog posts, forum comments, and note-taking. Its key advantages include simplicity, portability (plain text files work anywhere), readability even in raw form, and easy conversion to HTML and other formats. With an online Markdown previewer like this tool, you can instantly see how your Markdown renders as HTML.

GFM (GitHub Flavored Markdown) is an extension of standard Markdown developed by GitHub. It adds several useful features including tables, task lists (- [ ] and - [x]), strikethrough (~~text~~), auto-linked URLs, and syntax-highlighted code blocks with language specifiers. Our Markdown previewer uses the marked library with GFM support enabled, so all these features render correctly in the live preview.

Tables are created using pipes (|) and hyphens (-). Here's an example:

| Header 1 | Header 2 | Header 3 |
|----------|----------|----------|
| Cell 1 | Cell 2 | Cell 3 |
| Cell 4 | Cell 5 | Cell 6 |

You can align columns by adding colons in the separator row: :--- for left, :---: for center, ---: for right alignment. The live preview will instantly show your formatted table.

Use triple backticks (```) followed by the language name to create a fenced code block. For example:

```javascript
function hello() {
console.log("Hello World!");
}
```

While our previewer displays code blocks with clear formatting, for full syntax highlighting you can pair this tool with libraries like highlight.js or Prism.js. The rendered HTML output preserves language tags for integration with these highlighters.

Markdown is a simplified markup language designed for readability in plain text, while HTML is the full-featured language of the web. Markdown is easier to write and read in raw form, making it ideal for content creation. HTML offers complete control over layout and styling but is more verbose. Markdown is typically converted to HTML for display in browsers—which is exactly what this online Markdown previewer does in real-time. You can also embed raw HTML directly within Markdown for advanced formatting needs.

This tool runs entirely in your browser. Once the page is loaded, the Markdown to HTML rendering happens locally using the marked JavaScript library. No data is sent to any server. Your content is automatically saved to your browser's localStorage, so you can close the page and return later without losing your work. For full offline use, you can save this page to your device.

Our Markdown previewer offers multiple export options: Copy HTML to clipboard (ready to paste into a CMS or website), and Download HTML to save a complete .html file with embedded styling. You can also Copy Markdown to preserve the original source. These features make it easy to move between writing and publishing workflows without friction.

• Nested lists: Indent with 2 or 4 spaces for sub-items.
• Footnotes: Some parsers support [^1] footnote references.
• Definition lists: Supported in some extended Markdown flavors.
• Escaping: Use backslash (\) before special characters like \* \# \[ to display them literally.
• Line breaks: End a line with two spaces or use <br> for forced breaks.
• HTML in Markdown: You can embed raw HTML tags directly for complex layouts.