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How to Generate URL Slugs (SEO-Friendly URLs)

Published on February 10, 2026

What Is a URL Slug?

A URL slug is the part of a web address that identifies a specific page in a human-readable format. It appears after the domain name and any path prefixes. For example, in the URL https://example.com/blog/how-to-generate-url-slug, the slug is how-to-generate-url-slug.

The term "slug" originated in newspaper publishing, where it referred to a short label for an article used internally during editing. In web development, it serves the same purpose — a concise, descriptive identifier for a piece of content. Good slugs are readable by humans, parsable by search engines, and stable over the lifetime of a page.

Compare these two URLs:

# Bad: opaque ID, tells the reader nothing
https://example.com/posts/8f14e45f-ceea-41a6-a6ee-12345678

# Good: descriptive slug, immediately understandable
https://example.com/blog/how-to-generate-url-slug

The second URL tells both the user and search engines exactly what the page contains before anyone clicks on it.

Why Slugs Matter for SEO

Search engines use URLs as one of many ranking signals. While the URL alone will not make or break your rankings, a well-crafted slug provides several concrete SEO benefits:

  • Keyword relevance. Including your target keyword in the slug confirms to search engines what the page is about. A URL like /blog/url-slug-generator reinforces that the page is about URL slug generation.
  • Click-through rate. In search results, the URL is displayed below the title. A clean, readable URL gives users confidence that the page matches their intent. Studies have shown that descriptive URLs receive more clicks than cryptic ones.
  • Link sharing. When someone shares your URL in a chat, email, or social media post, a readable slug serves as its own description. Recipients are more likely to click a link they can understand at a glance.
  • Site structure signals. URLs with logical path segments (like /blog/category/post-title) help search engines understand your site's information architecture.
  • Anchor text in raw links. When other sites link to your page using the raw URL as anchor text, a keyword-rich slug passes more topical relevance than a random ID.

Slug Best Practices

Follow these rules to generate clean, effective URL slugs every time:

  1. Use lowercase only. URLs are case-sensitive on most servers. Using lowercase prevents duplicate content issues where /Blog/My-Post and /blog/my-post serve different pages or require redirects.
  2. Separate words with hyphens. Hyphens are the standard word separator in URLs. Search engines treat hyphens as spaces between words. Underscores are not treated as word separators by Google — url_slug is read as one word, while url-slug is read as two.
  3. Keep it short. Aim for 3 to 5 words. Remove filler words like "a", "the", "and", "or", "is", "in", and "to" unless they are essential for meaning. Shorter URLs are easier to remember, share, and display in search results.
  4. Use only URL-safe characters. Stick to lowercase letters (a-z), digits (0-9), and hyphens (-). Avoid spaces, special characters, and non-ASCII characters in the slug itself.
  5. Remove consecutive hyphens. After stripping special characters, you may end up with double hyphens like my--post. Collapse them into a single hyphen.
  6. Do not end with a hyphen. Trailing hyphens look unfinished and can cause issues with some URL parsers. Trim them.
# Input title -> Generated slug

"How to Generate URL Slugs (SEO-Friendly URLs)"
-> how-to-generate-url-slugs

"10 Tips & Tricks for Better Web Scraping"
-> 10-tips-tricks-better-web-scraping

"What is JSON? A Beginner's Guide"
-> what-is-json-beginners-guide

"Café, Naïve, & Résumé: Handling Accents"
-> cafe-naive-resume-handling-accents

"C++ vs. Rust: Performance Comparison (2026)"
-> cpp-vs-rust-performance-comparison-2026

Handling Accents and Special Characters

Many languages use accented characters (diacritics) that need special handling in URLs. The standard approach is called "transliteration" — converting accented characters to their closest ASCII equivalent:

# Transliteration examples
é -> e    (café -> cafe)
ñ -> n    (español -> espanol)
ü -> u    (über -> uber)
ö -> o    (Köln -> koln)
ç -> c    (façade -> facade)
ß -> ss   (Straße -> strasse)
ø -> o    (Ørsted -> orsted)
å -> a    (Malmö -> malmo)
ä -> a    (Ärger -> arger)
ł -> l    (Łódź -> lodz)
đ -> d    (Đà Nẵng -> da-nang)

Unicode normalization (NFD) decomposes accented characters into a base letter plus combining marks. You can then strip the combining marks to get the ASCII equivalent. Here is how to implement this in JavaScript:

function generateSlug(title) {
  return title
    // Normalize accented characters (NFD decomposition)
    .normalize("NFD")
    // Remove combining diacritical marks
    .replace(/[\u0300-\u036f]/g, "")
    // Convert to lowercase
    .toLowerCase()
    // Replace non-alphanumeric characters with hyphens
    .replace(/[^a-z0-9]+/g, "-")
    // Remove leading/trailing hyphens
    .replace(/^-+|-+$/g, "")
    // Collapse consecutive hyphens
    .replace(/-{2,}/g, "-");
}

// Examples
generateSlug("How to Generate URL Slugs");
// "how-to-generate-url-slugs"

generateSlug("Café Naïve Résumé");
// "cafe-naive-resume"

generateSlug("10 Tips & Tricks for Web Scraping!!!");
// "10-tips-tricks-for-web-scraping"

generateSlug("Ärger mit Ölförderung in Österreich");
// "arger-mit-olforderung-in-osterreich"

generateSlug("---Hello   World---");
// "hello-world"

Python Implementation

import re
import unicodedata

def generate_slug(title: str) -> str:
    # Normalize accented characters (NFD decomposition)
    normalized = unicodedata.normalize("NFD", title)
    # Remove combining diacritical marks
    ascii_text = normalized.encode("ascii", "ignore").decode("ascii")
    # Convert to lowercase
    lowered = ascii_text.lower()
    # Replace non-alphanumeric characters with hyphens
    slug = re.sub(r"[^a-z0-9]+", "-", lowered)
    # Remove leading/trailing hyphens
    slug = slug.strip("-")
    # Collapse consecutive hyphens
    slug = re.sub(r"-{2,}", "-", slug)
    return slug

# Examples
print(generate_slug("How to Generate URL Slugs"))
# "how-to-generate-url-slugs"

print(generate_slug("Café Naïve Résumé"))
# "cafe-naive-resume"

print(generate_slug("What is JSON? A Beginner's Guide"))
# "what-is-json-a-beginners-guide"

Examples from Popular Websites

Looking at how major websites structure their URLs reveals consistent patterns. Here are real-world examples of good slug practices:

# GitHub (repo and file slugs)
github.com/facebook/react
github.com/vercel/next.js
github.com/microsoft/typescript

# Stack Overflow (ID + slug for SEO)
stackoverflow.com/questions/12345/how-to-parse-json-in-javascript

# MDN Web Docs (path-based hierarchy)
developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

# Dev.to (username + slug)
dev.to/username/how-to-build-a-rest-api-with-node-js-1abc

# Medium (slug + random suffix)
medium.com/@user/how-to-learn-web-development-abc123def456

# WordPress (date-based or slug-only)
example.com/2026/02/how-to-generate-url-slugs/
example.com/how-to-generate-url-slugs/

Notice the common patterns: all lowercase, hyphens as separators, descriptive words, and no unnecessary characters. Some sites like Stack Overflow include an ID for uniqueness while still appending a slug for readability — the slug is optional and exists purely for human and SEO benefit.

Slug Generation in Frameworks

Most web frameworks provide built-in slug generation or have popular libraries for it:

# Ruby on Rails (built-in parameterize)
"How to Generate URL Slugs".parameterize
# => "how-to-generate-url-slugs"

# Django (built-in slugify)
from django.utils.text import slugify
slugify("How to Generate URL Slugs")
# => "how-to-generate-url-slugs"

# Laravel PHP (built-in Str::slug)
use Illuminate\Support\Str;
Str::slug("How to Generate URL Slugs");
// => "how-to-generate-url-slugs"

# Node.js (using the "slugify" npm package)
import slugify from "slugify";
slugify("How to Generate URL Slugs", { lower: true, strict: true });
// => "how-to-generate-url-slugs"

# Go (using the "slug" package)
import "github.com/gosimple/slug"
slug.Make("How to Generate URL Slugs")
// => "how-to-generate-url-slugs"

Common Mistakes to Avoid

  • Including dates unnecessarily. A URL like /blog/2026/02/10/how-to-generate-slugs bakes in a date that makes the content look stale once time passes. Use dateless URLs unless your content is inherently time-bound (like news articles).
  • Changing slugs after publishing. Once a page is indexed and linked to, changing its slug breaks all existing links and loses accumulated SEO value. If you must change a slug, set up a 301 redirect from the old URL to the new one.
  • Using stop words excessively. "the", "a", "an", "is", "in", "to", "for" add length without adding meaning. Remove them unless the slug becomes ambiguous without them.
  • Including query parameters in slugs. Slugs belong in the URL path, not as query strings. Use /products/wireless-mouse instead of /products?name=wireless-mouse.
  • Making slugs too long. URLs over 75 characters get truncated in search results. Keep slugs to 3-5 meaningful words for best results.
  • Using encoded characters. URLs with %20 (space), %C3%A9 (accented e), or other percent-encoded sequences are harder to read and share. Transliterate instead.

Slug Uniqueness and Collision Handling

In any application with user-generated content, two articles might produce the same slug. You need a strategy for handling collisions. The most common approaches are:

// Approach 1: Append a numeric suffix
how-to-generate-url-slugs
how-to-generate-url-slugs-2
how-to-generate-url-slugs-3

// Approach 2: Append a short random hash
how-to-generate-url-slugs-a1b2c3

// Approach 3: Prepend a unique ID (Stack Overflow style)
/questions/12345/how-to-generate-url-slugs
/questions/67890/how-to-generate-url-slugs

// Implementation example (JavaScript)
async function uniqueSlug(title, checkExists) {
  let slug = generateSlug(title);
  let suffix = 1;

  while (await checkExists(slug)) {
    suffix++;
    slug = generateSlug(title) + "-" + suffix;
  }

  return slug;
}

// Usage
const slug = await uniqueSlug(
  "How to Generate URL Slugs",
  (s) => db.posts.exists({ slug: s })
);

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Try the Slug Generator

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