What is a URL Slug?

A URL slug is the part of a web address that comes after the domain name and identifies a specific page in a human-readable format. For example, in https://example.com/blog/my-first-post, the slug is "my-first-post".

Slugs originated from newspaper publishing, where a "slug" was a short name given to a story for internal reference. In web development, slugs serve the same purpose—providing a clean, readable identifier for content.

Why Slugs Matter for SEO

URL slugs are a significant ranking factor for search engines. Well-crafted slugs help in several ways:

Slug Best Practices

Practice	Good Example	Bad Example
Use hyphens, not underscores	seo-best-practices	seo_best_practices
Keep it lowercase	about-us	About-Us
Remove special characters	faqs-answered	faq's-answered
Keep it short	python-tutorial	complete-beginner-python-programming-tutorial-2024
Include target keyword	javascript-array-methods	article-12345
Remove stop words	improve-website-speed	how-to-improve-the-speed-of-your-website

Hyphens vs. Underscores

Common Slug Mistakes to Avoid

• Auto-generated IDs: /post/123456 tells users and search engines nothing about the content
• Dates in slugs: /2024/01/15/post-title makes content look outdated when still relevant
• Changing slugs: Modifying slugs breaks existing links and loses SEO value (use 301 redirects if necessary)
• Keyword stuffing: /cheap-seo-best-seo-top-seo-services looks spammy and hurts rankings
• Duplicate slugs: Same slug on different pages causes confusion and duplicate content issues

Slug Handling in Popular Platforms

Programmatic Slug Generation

Most frameworks provide slug generation utilities:

# Python
from django.utils.text import slugify
slug = slugify("My Blog Post Title!")  # "my-blog-post-title"

# JavaScript
const slug = text
    .toLowerCase()
    .replace(/[^\w\s-]/g, '')
    .replace(/\s+/g, '-');

# Ruby
"My Blog Post".parameterize  # "my-blog-post"

# PHP
$slug = preg_replace('/[^a-z0-9]+/', '-', strtolower($text));

Internationalization (i18n) Considerations

For non-English content, you have options:

• Transliterate: Convert characters to ASCII equivalents (é → e, ü → u)
• Keep Unicode: Modern browsers support UTF-8 URLs (/café-guide)
• URL encode: Convert to percent-encoded format (/caf%C3%A9-guide)

Google can index both transliterated and Unicode URLs, but transliterated versions are safer for maximum compatibility.