Text to Slug — The Complete Guide

Convert any title or phrase into a clean, readable, and SEO-friendly URL slug. This guide covers slug rules, best practices, transliteration, multilingual issues, uniqueness, implementation examples in JavaScript and Python, CMS tips, and common pitfalls.

What is a Slug?

A slug is the part of a URL that identifies a specific page in a human-readable way. For example, in https://example.com/blog/how-to-make-coffee, the slug is how-to-make-coffee. Slugs are designed to be short, clear, and often optimized for search engines and users.

Why Slugs Matter

• SEO: Search engines use slugs as ranking signals — including keywords in the slug can help relevance.
• Usability: A clear slug tells visitors what the page is about at a glance.
• Shareability: Short, readable slugs are easier to share and remember.
• Accessibility: Clean slugs improve the experience for screen readers and protocols that use URLs.

Rules & Best Practices for Creating Slugs

Common Slug Examples

How to Convert Text to a Slug — Step-by-Step

1. Trim whitespace from ends and collapse multiple spaces.
2. Normalize case to lowercase.
3. Transliterate or remove diacritics (e.g., "café" → "cafe").
4. Remove punctuation & symbols (except hyphens).
5. Replace spaces and separators with a single hyphen.
6. Remove duplicate hyphens and trim leading/trailing hyphens.
7. Optionally remove stop words like "and", "the", "of".
8. Ensure uniqueness by checking the target path and appending a suffix if necessary.

Simple Slugify Example — JavaScript

Client-side, quick slug function (handles accents using String.prototype.normalize):

function slugify(text) {
  return String(text)
    .normalize('NFKD')                // split accents
    .replace(/[\u0300-\u036f]/g, '')  // remove diacritics
    .toLowerCase()
    .trim()
    .replace(/[^\w\s-]/g, '')         // remove non-word chars
    .replace(/\s+/g, '-')             // replace spaces with hyphen
    .replace(/--+/g, '-')             // collapse multiple hyphens
    .replace(/^-+|-+$/g, '');         // trim hyphens
}
// Usage:
console.log(slugify("10 Best Café Machines — 2025!")); // "10-best-cafe-machines-2025"

Note: \w in JavaScript includes underscores — we remove punctuation first to avoid underscores in the slug.

Robust Slugify — Python Example

Use the unidecode library for better transliteration in Python:

pip install Unidecode

from unidecode import unidecode
import re

def slugify(text):
    text = unidecode(text)           # transliterate to ASCII
    text = text.lower().strip()
    text = re.sub(r'[^a-z0-9\s-]', '', text)  # remove punctuation
    text = re.sub(r'[\s-]+', '-', text)       # collapse spaces and hyphens
    return text.strip('-')

print(slugify("Café & Pastries: The Best!"))  # "cafe-pastries-the-best"

Handling Non-Latin Scripts & Multilingual Content

Options for non-Latin content depend on your platform and audience:

• Transliteration: Convert scripts into Latin equivalents (recommended for broader compatibility). Use libraries like unidecode (Python) or lookups for languages like Chinese (pinyin) or Arabic.
• UTF-8 Slugs: Modern systems support UTF-8 in URLs — you could keep native characters (e.g., /zh/北京-旅游). Be mindful of percent-encoding and readability when sharing links.
• Hybrid: Keep a short transliterated slug for the public URL and a native-title meta for display.

Stop Words: Remove or Keep?

Stop words (a, an, the, of, in, on) can be removed to shorten slugs. Example:

• Title: The Best Guide to Traveling in Europe
• Slug w/ stop words: the-best-guide-to-traveling-in-europe
• Slug without stop words: best-guide-traveling-europe

Both are acceptable. Removing stop words reduces length, but including them can make the slug read more naturally. Choose a consistent policy for your site.

Uniqueness & Collision Handling

Two methods to prevent duplicate slugs:

1. Database check: When saving a new slug, query existing slugs. If collision exists, append -2, -3, etc., or the resource ID (-123).
2. Namespace by date or category: Include a year or parent collection in the path (e.g., /blog/2025/best-coffee-makers).

function uniqueSlug(base, existsFn) {
  let slug = base;
  let i = 1;
  while (existsFn(slug)) {
    i += 1;
    slug = base + '-' + i;
  }
  return slug;
}

Where existsFn checks the data store for slug existence.

Preserving Old Slugs — Redirect Strategy

If you change a page slug, you should keep the old URL working by issuing a 301 redirect to the new slug. This preserves SEO value and avoids broken links.

• Store historical slugs in your database and map them to the current record.
• When a request matches an old slug, return a 301 redirect to the canonical slug.
• Update internal links to the new canonical slug to avoid redirect chains.

Slug Length & Readability

Keep slugs short — ideally under 60 characters so they display cleanly in search results. Prioritize clarity: a readable slug can increase click-through rates.

SEO Considerations

• Use important keywords early in the slug.
• Avoid keyword stuffing — a natural, readable slug is better for users and search engines.
• Keep the URL structure shallow; deeper paths can still rank but simple paths are preferred.
• Use rel="canonical" tags if content is accessible under multiple slugs/paths.

Edge Cases & Pitfalls

• Empty slugs: If the title contains only symbols or is empty after cleaning, fall back to a default like page + ID.
• Numerical slugs: Pure numerical slugs can conflict with IDs; avoid them or namespace them (e.g., post-123).
• Reserved words: Avoid using reserved path segments like admin, api, or login as top-level slugs.
• Security: Sanitize slugs to prevent injection in file paths or shell commands if slugs are used in filenames or system calls.

Libraries & Tools

Popular slugify libraries:

• JavaScript: slugify (npm), speakingurl
• Python: python-slugify, Unidecode
• PHP: laravel Str::slug(), slugify
• Ruby: stringex, friendly_id

Quick FAQ

Q: Should slugs be human-readable or machine-friendly?

A: Both. Aim for human-readable slugs that follow machine-safe rules (lowercase, hyphens, ASCII when possible).

Q: Are accents allowed in slugs?

A: Modern systems can support UTF-8 slugs, but for maximum compatibility and shareability transliteration is recommended.

Q: What separator should I use — hyphen or underscore?

A: Use hyphens. Search engines treat hyphens as word separators; underscores are less ideal.

Q: How to handle very long titles?

A: Shorten aggressively: keep the core keyword and meaningful words; drop filler words.

Final Thoughts

Creating clean, consistent, and SEO-friendly slugs is a small but important step in building a polished web presence. Follow the rules — lowercase, hyphens, transliterate accents, keep slugs short, ensure uniqueness, and redirect old slugs — and you'll have URLs that both users and search engines like.

If you'd like, I can generate a production-ready slugify utility for your stack (JavaScript, Python, PHP, or Ruby) with uniqueness checks and transliteration rules — tell me which language and database you use.