The Complete Guide to Writing in MDX

MDX is a powerful format that combines Markdown with JSX, allowing you to use React components directly in your markdown content. This guide will walk you through everything you need to know to write effective MDX content.

Basic Markdown Syntax

Before diving into the advanced features of MDX, let's review basic markdown syntax:

Headings

Use # symbols for headings:

# Heading 1
## Heading 2
### Heading 3
#### Heading 4
##### Heading 5
###### Heading 6

Text Formatting

• Bold text is created with **double asterisks**
• Italic text is created with *single asterisks*
• ~~Strikethrough~~ is created with ~~double tildes~~
• Inline code is created with backticks

Lists

Unordered lists use asterisks, plus signs, or hyphens:

• Item 1
• Item 2
  • Nested item 2.1
  • Nested item 2.2
• Item 3

Ordered lists use numbers:

1. First item
2. Second item
3. Third item

Links and Images

Create links with [link text](URL): Visit Next.js Documentation

Add images with ![alt text](image-url):

Blockquotes

Blockquotes are created using the greater-than symbol.

You can have multiple paragraphs in a blockquote by adding a > on empty lines between paragraphs.

Code Blocks

Create code blocks with triple backticks and specify the language:

function greeting(name) {
  return `Hello, ${name}!`;
}

console.log(greeting('MDX User'));

MDX-Specific Features

Now let's explore what makes MDX special - the ability to use JSX and React components!

Embedding React Components

You can import and use React components directly in your MDX files:

import { Button } from '@/components/ui/button';

<Button>Click Me!</Button>

Exporting Variables

You can export variables from your MDX file:

export const metadata = {
  author: 'Jane Doe',
  readingTime: '5 min',
};

Using JavaScript Expressions

You can use JavaScript expressions within curly braces:

{3 + 4}

This will render as: 7

Creating Dynamic Content

You can create dynamic content with JavaScript:

{['React', 'Next.js', 'MDX'].map(tech => (
  <li key={tech}>{tech}</li>
))}

Creating Custom Components

You can even define components within your MDX:

export const Highlight = ({children}) => (
  <span style={{backgroundColor: 'yellow', padding: '2px 4px', borderRadius: '4px'}}>
    {children}
  </span>
);

This is a paragraph with a <Highlight>highlighted phrase</Highlight>.

Advanced MDX Features

MDX allows you to do even more complex things:

Using Frontmatter

As you can see at the top of this file, MDX supports frontmatter for metadata:

---
title: "The Complete Guide to Writing in MDX"
date: "2025-05-10"
excerpt: "Learn everything you need to know about writing content in MDX format."
---

Using MDX Layouts

You can define layouts for your MDX content:

import MyLayout from '@/components/MyLayout';

export default function MDXLayout({ children }) {
  return <MyLayout>{children}</MyLayout>;
}

Embedding Interactive Elements

MDX shines when creating interactive content:

import { CounterDemo } from '@/components/CounterDemo';

<CounterDemo initialCount={5} />

Best Practices for MDX

1. Keep components simple - Complex components are harder to maintain
2. Don't overuse components - Sometimes plain markdown is more readable
3. Be mindful of hydration - Interactive components need client-side hydration
4. Use proper semantic HTML - Helps with accessibility and SEO
5. Test your MDX content - Especially when using custom components

Troubleshooting Common Issues

Components Not Rendering

If your components aren't rendering, check:

• Component imports are correct
• You're using the proper MDX processing library
• The component is available to the MDX renderer

Syntax Errors

MDX is strict about JSX syntax. Common issues include:

• Unclosed JSX tags
• Missing curly braces around expressions
• Incorrect nesting of components

Styling Issues

When styling MDX content:

• Consider using a CSS-in-JS solution
• Use global styles for markdown elements
• Be mindful of specificity conflicts

Conclusion

MDX offers the perfect blend of simple markdown syntax and powerful React components. By mastering MDX, you can create rich, interactive content while maintaining the simplicity of markdown for your main content.

Remember that MDX is processed at build time by default, so your React components need to be compatible with your chosen rendering strategy (Static Generation or Server-side Rendering).

Now you're ready to create amazing content with MDX!

This guide was last updated on May 10, 2025