URL Slugs Explained: How to Create SEO-Friendly URLs

What Is a URL Slug?

A slug is the human-readable, URL-friendly part of a web address that identifies a specific page. The word "slug" comes from newspaper typography, where it referred to the short name given to a story in production.

Example URL with slug: https://example.com/blog/how-to-bake-sourdough-bread The slug is: how-to-bake-sourdough-bread

Slugs appear in blog posts, product pages, news articles, user profiles, and anywhere URLs need to be descriptive and shareable.

What Makes a Good Slug?

A well-formed slug:

• Uses only lowercase letters, numbers, and hyphens
• Has no spaces (replaced with hyphens)
• Has no special characters (removed or transliterated)
• Has no consecutive or trailing hyphens
• Is concise but descriptive (30-60 characters ideal)
• Contains the primary keyword for SEO

Slugification Algorithm

Converting any text to a slug involves several steps:

1. Unicode normalization: Decompose characters (e.g., é → e + combining accent)
2. Transliteration: Convert non-ASCII to closest ASCII equivalent
3. Lowercase: Convert to all lowercase
4. Remove special characters: Keep only letters, numbers, and spaces
5. Replace spaces with hyphens: The hyphen is the standard word separator
6. Remove consecutive hyphens: Replace multiple hyphens with single
7. Trim hyphens: Remove leading and trailing hyphens

Example transformation:

Input:  "The World's Best Café & Restaurant!"
Step 1: "The World's Best Cafe & Restaurant!"  (café → cafe)
Step 3: "the world's best cafe & restaurant!"  (lowercase)
Step 4: "the worlds best cafe  restaurant"     (remove ' & !)
Step 5: "the-worlds-best-cafe--restaurant"     (spaces to hyphens)
Step 6: "the-worlds-best-cafe-restaurant"      (remove double --)
Output: "the-worlds-best-cafe-restaurant"

Language-Specific Considerations

German (Umlauts)

German umlauts have standard transliterations:

• ä → ae
• ö → oe
• ü → ue
• ß → ss

"Schöne Grüße" → "schoene-gruesse"

French and Spanish Accents

Accented characters map to their base form:

• é, è, ê, ë → e
• à, â, ä → a
• ñ → n
• ç → c

CJK Characters (Chinese, Japanese, Korean)

CJK characters cannot be transliterated to meaningful Latin slugs. Options:

• Use pinyin romanization for Chinese
• Use romaji for Japanese
• Use the English translation for the page title
• Use a hash or ID-based slug

Arabic, Hebrew, Russian

Right-to-left scripts and Cyrillic often require locale-specific transliteration rules.

SEO Best Practices for Slugs

Use Keywords

The slug is a ranking factor in Google's algorithm. Include the primary keyword naturally:

• Good: how-to-install-postgresql
• Avoid: post-1234 or page-2024-01-15

Keep It Short

Shorter URLs are more shareable and cleaner:

• Good: /blog/sourdough-bread-recipe
• Avoid: /blog/how-to-make-delicious-homemade-sourdough-bread-step-by-step-guide

Use Hyphens, Not Underscores

Google treats hyphens as word separators and underscores as word joiners:

• bread-recipe → "bread" and "recipe" are separate keywords
• bread_recipe → treated as single word "bread_recipe"

Avoid Stop Words

Remove common words that don't add SEO value:

• the, a, an, and, or, but, in, on, at

"how-to-bake-a-delicious-bread" can become "how-to-bake-delicious-bread"

Handle Duplicates

When creating slugs from user-generated content, implement uniqueness:

• my-post → already exists → my-post-2 → exists → my-post-3
• Or use a random suffix: my-post-a7b9

Slugs in Different Frameworks

Next.js (Dynamic Routes)

File: pages/blog/[slug].js

export async function getStaticProps({ params }) {
  const post = getPostBySlug(params.slug);
  return { props: { post } };
}

Express.js

app.get('/posts/:slug', (req, res) => {
  const post = db.posts.findBySlug(req.params.slug);
  res.render('post', { post });
});

Django

from django.utils.text import slugify
slug = slugify("Hello World!")  # "hello-world"

Using the Slugify Tool

Our tool:

1. Enter any text — titles, names, phrases in any language
2. Instant slug output — see the converted slug in real time
3. Multiple options — configure separator character, case, stop word removal
4. Unicode handling — proper transliteration of accented and special characters
5. Copy slug — one-click copy for immediate use

Use it for generating consistent slugs for blog posts, product names, category pages, and any URL that needs to be human-readable and SEO-friendly.