Slug Generator

What Is a URL Slug?

A URL slug is the part of a web address that identifies a specific page in a human-readable form. In the URL https://example.com/blog/my-first-post, the slug is my-first-post. A slug generator transforms a page title or description into a string that contains only lowercase letters, numbers, and hyphens (or another chosen separator). This process removes spaces, strips accents and diacritics, drops special characters, and normalizes whitespace into single separators.

Slug generation is a standard step in content management systems, static site generators, blog platforms, and any application that derives URLs from user input. WordPress, Ghost, Hugo, Next.js, and Django all include slug generation logic because readable URLs improve both usability and search engine optimization. A well-formed slug tells the user what a page contains before they click the link.

The term "slug" comes from newspaper publishing, where it referred to a short label used to identify a story during production. In web development, the slug performs the same function: it is a compact, unique, URL-safe identifier derived from a longer title or name. Because slugs are derived programmatically, a reliable slug generator ensures consistency across every page and locale.

Why Use This Slug Generator?

Manually creating URL slugs is error-prone. Forgetting to strip an accent, leaving a double hyphen, or missing an edge case with Unicode input can produce broken or ugly URLs. This tool handles those problems automatically.

Slug Generator Use Cases

Slug Generation Rules and Character Handling

Slug generation follows a predictable sequence of transformations. Understanding each step helps you debug unexpected output or build your own slugify function.

1. 1. Unicode Normalization (NFD)

   Decompose combined characters into base character + combining mark. For example, é (U+00E9) becomes e + combining acute accent (U+0301). This makes diacritics removable in the next step.
2. 2. Strip Diacritics

   Remove all characters in the Unicode Combining Diacritical Marks block (U+0300–U+036F). After this step, café becomes cafe and Ñ becomes N.
3. 3. Remove Special Characters

   Replace any character that is not a letter, digit, whitespace, or hyphen with a space. This drops punctuation, symbols, and characters that have no ASCII equivalent.
4. 4. Trim and Collapse Whitespace

   Remove leading and trailing whitespace, then collapse all runs of consecutive spaces, underscores, or hyphens into a single chosen separator.
5. 5. Apply Case and Separator

   Convert to lowercase (optional) and join words with the chosen separator character: hyphen (-), underscore (_), or dot (.).

Character Transformation Reference

The table below shows how common characters are handled during slug generation:

Code Examples

Slug generation in popular languages and frameworks. Each example handles Unicode normalization, diacritic removal, and separator insertion.

function slugify(text, separator = '-') {
  return text
    .normalize('NFD')                   // decompose accented chars
    .replace(/[\u0300-\u036f]/g, '')    // strip diacritics
    .toLowerCase()
    .replace(/[^\w\s-]/g, ' ')          // drop special chars
    .trim()
    .replace(/[\s_-]+/g, separator)     // collapse whitespace → separator

  // slugify('Café au Lait')      → "cafe-au-lait"
  // slugify('Hello World', '_')  → "hello_world"
}

// Node.js alternative using the `slugify` npm package:
// npm install slugify
// const slugify = require('slugify')
// slugify('Hello World', { lower: true, strict: true }) → "hello-world"

import re
import unicodedata

def slugify(text: str, separator: str = '-') -> str:
    """Convert text to a URL-safe slug."""
    text = unicodedata.normalize('NFD', text)
    text = text.encode('ascii', 'ignore').decode('ascii')  # strip non-ASCII
    text = text.lower()
    text = re.sub(r'[^\w\s-]', ' ', text)
    text = text.strip()
    text = re.sub(r'[\s_-]+', separator, text)
    return text

# slugify('Café au Lait')      → "cafe-au-lait"
# slugify('Hello World', '_')  → "hello_world"

# Alternative: python-slugify (pip install python-slugify)
# from slugify import slugify
# slugify('Café au Lait')  → "cafe-au-lait"

package main

import (
	"regexp"
	"strings"
	"unicode"

	"golang.org/x/text/unicode/norm"
	"golang.org/x/text/transform"
	"golang.org/x/text/runes"
)

func slugify(text string) string {
	// NFD normalize and strip diacritics
	t := transform.Chain(norm.NFD, runes.Remove(runes.In(unicode.Mn)), norm.NFC)
	result, _, _ := transform.String(t, text)

	result = strings.ToLower(result)
	re := regexp.MustCompile(`[^\w\s-]+`)
	result = re.ReplaceAllString(result, " ")
	result = strings.TrimSpace(result)
	re = regexp.MustCompile(`[\s_-]+`)
	result = re.ReplaceAllString(result, "-")
	return result
}

// slugify("Café au Lait") → "cafe-au-lait"
// slugify("Hello World")  → "hello-world"

function slugify(string $text, string $separator = '-'): string {
    // Transliterate non-ASCII characters
    $text = transliterator_transliterate(
        'Any-Latin; Latin-ASCII; Lower()', $text
    );
    // Remove anything that is not a word char, space, or hyphen
    $text = preg_replace('/[^\w\s-]/', ' ', $text);
    $text = trim($text);
    $text = preg_replace('/[\s_-]+/', $separator, $text);
    return $text;
}

// slugify('Café au Lait')      → "cafe-au-lait"
// slugify('Hello World', '_')  → "hello_world"

Frequently Asked Questions