Format code

Format code in your documentation with syntax highlighting, line numbers, diffs, copy buttons, and interactive code group features in MDX.

Add code samples

You can add inline code snippets or code blocks. Code blocks support meta options for syntax highlighting, titles, line highlighting, icons, and more.

Inline code

To denote a word or phrase as code, enclose it in backticks (`).

To denote a `word` or `phrase` as code, enclose it in backticks (`).

Code blocks

Use fenced code blocks by enclosing code in three backticks. Code blocks are copyable, and if you have the assistant enabled, users can ask the assistant to explain the code.

Specify the programming language for syntax highlighting and to enable meta options. Add any meta options, like a title or icon, after the language.

HelloWorld.java example

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

```java HelloWorld.java example lines icon="java"
class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}
```

Code block options

Add meta options to your code blocks to customize their appearance.

You must specify a programming language for a code block before adding any other meta options.

Option syntax

• String and boolean options: Wrap with "", '', or no quotes.
• Expression options: Wrap with {}, "", or ''.

Syntax highlighting

Enable syntax highlighting by specifying the programming language after the opening backticks of a code block.

Mintlify uses Shiki for syntax highlighting and supports all available languages. See the full list of languages in Shiki’s documentation.

Customize code block themes globally using styling.codeblocks in your docs.json file. Set simple themes like system or dark, or configure custom Shiki themes for light and dark modes. See Settings for configuration options.

Syntax highlighting example

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

```java Syntax highlighting example
class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}
```

Custom syntax highlighting theme

For custom themes, set your theme in docs.json to "css-variables" and override syntax highlighting colors using CSS variables with the --mint- prefix.

The following variables are available:

Basic colors

• --mint-color-text: Default text color
• --mint-color-background: Background color

Token colors

• --mint-token-constant: Constants and literals
• --mint-token-string: String values
• --mint-token-comment: Comments
• --mint-token-keyword: Keywords
• --mint-token-parameter: Function parameters
• --mint-token-function: Function names
• --mint-token-string-expression: String expressions
• --mint-token-punctuation: Punctuation marks
• --mint-token-link: Links

ANSI colors

• --mint-ansi-black, --mint-ansi-black-dim
• --mint-ansi-red, --mint-ansi-red-dim
• --mint-ansi-green, --mint-ansi-green-dim
• --mint-ansi-yellow, --mint-ansi-yellow-dim
• --mint-ansi-blue, --mint-ansi-blue-dim
• --mint-ansi-magenta, --mint-ansi-magenta-dim
• --mint-ansi-cyan, --mint-ansi-cyan-dim
• --mint-ansi-white, --mint-ansi-white-dim
• --mint-ansi-bright-black, --mint-ansi-bright-black-dim
• --mint-ansi-bright-red, --mint-ansi-bright-red-dim
• --mint-ansi-bright-green, --mint-ansi-bright-green-dim
• --mint-ansi-bright-yellow, --mint-ansi-bright-yellow-dim
• --mint-ansi-bright-blue, --mint-ansi-bright-blue-dim
• --mint-ansi-bright-magenta, --mint-ansi-bright-magenta-dim
• --mint-ansi-bright-cyan, --mint-ansi-bright-cyan-dim
• --mint-ansi-bright-white, --mint-ansi-bright-white-dim

Custom syntax highlighting

Add syntax highlighting for languages not included in Shiki’s default set by providing custom TextMate grammar files. Create a JSON file following the TextMate grammar format, then reference it in your docs.json. You can add multiple custom languages by including additional paths in the array.

docs.json

{
  "styling": {
    "codeblocks": {
      "languages": {
        "custom": ["/languages/my-custom-language.json"]
      }
    }
  }
}

Twoslash

In JavaScript and TypeScript code blocks, use twoslash to enable interactive type information. Users can hover over variables, functions, and parameters to see types and errors like in an IDE.

Twoslash example

type Pet = "cat" | "dog" | "hamster";

function adoptPet(name: string, type: Pet) {
  return `${name} the ${type} is now adopted!`;
}

// Hover to see the inferred types
const message = adoptPet("Mintie", "cat");

```ts twoslash Twoslash example
type Pet = "cat" | "dog" | "hamster";

function adoptPet(name: string, type: Pet) {
  return `${name} the ${type} is now adopted!`;
}

// Hover to see the inferred types
const message = adoptPet("Mintie", "cat");
```

Title

Add a title to label your code example. Place the title after the language identifier. Titles can contain multiple words and file paths.

You can set the title two ways:

• Inline: Place the title directly after the language identifier.
• title property: Use title="Your title" for titles that need special characters or explicit quoting.

Example

const hello = "world";

const hello = "world";

```javascript Example title
const hello = "world";
```

```javascript title="utils/hello.js"
const hello = "world";
```

Icon

Add an icon to your code block using the icon property. See Icons for all available options.

Icon example

const hello = "world";

```javascript Icon example icon="square-js"
const hello = "world";
```

Line highlighting

Highlight specific lines in your code blocks using highlight with the line numbers or ranges you want to highlight.

Line highlighting example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Line highlighting example highlight={1-2,5}
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Line focusing

Focus on specific lines in your code blocks using focus with line numbers or ranges.

Line focusing example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Line focusing example focus={2,4-5}
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Show line numbers

Display line numbers on the left side of your code block using lines.

Show line numbers example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Show line numbers example lines
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Expandable

Allow users to expand and collapse long code blocks using expandable.

Expandable example

from datetime import datetime, timedelta
from typing import Dict, List, Optional
from dataclasses import dataclass

@dataclass
class Book:
title: str
author: str
isbn: str
checked_out: bool = False
due_date: Optional[datetime] = None

class Library:
    def __init__(self):
        self.books: Dict[str, Book] = {}
        self.checkouts: Dict[str, List[str]] = {} # patron -> list of ISBNs

    def add_book(self, book: Book) -> None:
        if book.isbn in self.books:
            raise ValueError(f"Book with ISBN {book.isbn} already exists")
        self.books[book.isbn] = book

    def checkout_book(self, isbn: str, patron: str, days: int = 14) -> None:
        if patron not in self.checkouts:
            self.checkouts[patron] = []

        book = self.books.get(isbn)
        if not book:
            raise ValueError("Book not found")

        if book.checked_out:
            raise ValueError("Book is already checked out")

        if len(self.checkouts[patron]) >= 3:
            raise ValueError("Patron has reached checkout limit")

        book.checked_out = True
        book.due_date = datetime.now() + timedelta(days=days)
        self.checkouts[patron].append(isbn)

    def return_book(self, isbn: str) -> float:
        book = self.books.get(isbn)
        if not book or not book.checked_out:
            raise ValueError("Book not found or not checked out")

        late_fee = 0.0
        if datetime.now() > book.due_date:
            days_late = (datetime.now() - book.due_date).days
            late_fee = days_late * 0.50

        book.checked_out = False
        book.due_date = None

        # Remove from patron's checkouts
        for patron, books in self.checkouts.items():
            if isbn in books:
                books.remove(isbn)
                break

        return late_fee

    def search(self, query: str) -> List[Book]:
        query = query.lower()
        return [
            book for book in self.books.values()
            if query in book.title.lower() or query in book.author.lower()
        ]

def main():
    library = Library()

    # Add some books
    books = [
        Book("The Hobbit", "J.R.R. Tolkien", "978-0-261-10295-4"),
        Book("1984", "George Orwell", "978-0-452-28423-4"),
    ]

    for book in books:
        library.add_book(book)

    # Checkout and return example
    library.checkout_book("978-0-261-10295-4", "patron123")
    late_fee = library.return_book("978-0-261-10295-4")
    print(f"Late fee: ${late_fee:.2f}")

if __name__ == "__main__":
    main()

```python Expandable example expandable
from datetime import datetime, timedelta
from typing import Dict, List, Optional
from dataclasses import dataclass

# ...

if __name__ == "__main__":
    main()
```

Wrap

Enable text wrapping for long lines using wrap. This prevents horizontal scrolling and makes long lines easier to read.

Wrap example

const greeting =
  "Hello, World! I am a long line of text that will wrap to the next line.";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Wrap example wrap
const greeting =
  "Hello, World! I am a long line of text that will wrap to the next line.";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Diff

Show a visual diff of added or removed lines in your code blocks. Added lines are highlighted in green and removed lines are highlighted in red.

Add [!code ++] or [!code --] inside a comment at the end of a line to mark it as added or removed. Use your language’s comment syntax:

Language	Added	Removed
JavaScript, TypeScript, Java, C, C++, Go, Rust	// [!code ++]	// [!code --]
Python, Ruby, Bash, YAML	# [!code ++]	# [!code --]
HTML, XML	<!-- [!code ++] -->	<!-- [!code --] -->
CSS	/* [!code ++] */	/* [!code --] */
SQL, Lua	-- [!code ++]	-- [!code --]

For multiple consecutive lines, add a colon and the number of lines:

• // [!code ++:3]: Mark the current line plus the next two lines as added.
• # [!code --:5]: Mark the current line plus the next four lines as removed.

JavaScript diff

const greeting = "Hello, World!"; 
function sayHello() {
  console.log("Hello, World!"); 
  console.log(greeting); 
}
sayHello();

def greet():
    print("Hello, World!")  
    print("Hello, Mintlify!")  

greet()

```js JavaScript diff lines
const greeting = "Hello, World!"; // [!code ++]
function sayHello() {
  console.log("Hello, World!"); // [!code --]
  console.log(greeting); // [!code ++]
}
sayHello();
```

```python Python diff lines
def greet():
    print("Hello, World!")  # [!code --]
    print("Hello, Mintlify!")  # [!code ++]

greet()
```

CodeBlock component

Use the <CodeBlock> component in custom React components to programmatically render code blocks with the same styling and features as markdown code blocks.

Props

language · string

The programming language for syntax highlighting.

filename · string

The filename to display in the code block header.

icon · string

The icon to display in the code block header. See Icons for available options.

lines · boolean

Whether to show line numbers.

wrap · boolean

Whether to wrap the code block.

expandable · boolean

Whether to expand the code block.

highlight · string

The lines to highlight. Provide a stringified array of numbers. Example: "[1,3,4,5]".

focus · string

The lines to focus on. Provide a stringified array of numbers. Example: "[1,3,4,5]".

Example

export const CustomCodeBlock = ({
  filename,
  icon,
  language,
  highlight,
  children,
}) => {
  return (
    <CodeBlock
      filename={filename}
      icon={icon}
      language={language}
      lines
      highlight={highlight}
    >
      {children}
    </CodeBlock>
  );
};