What are the key takeaways from this guide?

A slug is a URL-safe version of a string, typically derived from a title or name.. Convert accented characters to ASCII equivalents: ü → u, ñ → n, ø → o.. Two different titles can produce the same slug.. Keep slugs under 80 characters for readability and under 255 characters for filesystem compatibility.. Generate slugs on creation, not on every request.

Who is this guide for?

This guide is designed for beginner-level users and takes about 1 minutes to read.

Best Practice Beginner 1 min read 299 words

Slug and URL-Safe String Generation Best Practices

Slugs transform human-readable titles into URL-safe strings. Proper slug generation handles unicode, special characters, and collisions while preserving readability.

Key Takeaways

A slug is a URL-safe version of a string, typically derived from a title or name.
Convert accented characters to ASCII equivalents: ü → u, ñ → n, ø → o.
Two different titles can produce the same slug.
Keep slugs under 80 characters for readability and under 255 characters for filesystem compatibility.
Generate slugs on creation, not on every request

Featured Tool

Slug Generator

Convert text to URL-friendly slugs.

Try it Free

What Is a Slug

A slug is a URL-safe version of a string, typically derived from a title or name. 'How to Merge PDF Files' becomes how-to-merge-pdf-files. Slugs appear in URLs, filenames, and database identifiers.

Generation Rules

Step	Input	Output
1. Lowercase	'Hello World'	'hello world'
2. Transliterate	'café résumé'	'cafe resume'
3. Remove special chars	'hello! world?'	'hello world'
4. Replace spaces	'hello world'	'hello-world'
5. Collapse hyphens	'hello--world'	'hello-world'
6. Trim hyphens	'-hello-world-'	'hello-world'

Unicode Handling

Transliteration

Convert accented characters to ASCII equivalents: ü → u, ñ → n, ø → o. Libraries like python-slugify and slugify (npm) handle this automatically with locale-aware rules.

CJK Characters

Chinese, Japanese, and Korean characters do not transliterate to Latin. Options:

Keep original characters in the URL (modern browsers display them correctly)
Romanize: 東京 → tokyo (requires language-specific romanization libraries)
Use a numeric or UUID identifier instead

Collision Handling

Two different titles can produce the same slug. Handle collisions by appending a counter:

my-article
my-article-2
my-article-3

Check for existing slugs in the database before saving. Use a unique constraint as a safety net.

Length Considerations

Keep slugs under 80 characters for readability and under 255 characters for filesystem compatibility. Truncate at word boundaries to avoid cutting words in half.

Implementation Tips

Generate slugs on creation, not on every request
Make slugs immutable after creation (changing them breaks URLs)
If a title changes, keep the old slug and add a redirect to the new URL
Store slugs in a dedicated indexed column for fast lookups