A slug is the human-readable portion of a URL that identifies a specific page. For example, in "example.com/blog/my-great-post", the slug is "my-great-post". Slugs are lowercase, use hyphens instead of spaces, and contain only URL-safe characters.

Why are hyphens preferred over underscores in slugs?

Google treats hyphens as word separators (so "my-blog-post" is indexed as three separate words) but treats underscores as word joiners ("my_blog_post" is indexed as one word). For SEO, hyphens are the best practice for blog posts and page URLs.

What does transliterate do?

Transliteration converts accented or special characters to their closest ASCII equivalent. For example, "café" becomes "cafe", "jalapeño" becomes "jalapeno", and "über" becomes "uber". This ensures the slug is safe in any URL context.

When should I use a max length?

Many CMS platforms (WordPress, Shopify, etc.) truncate slugs at 200 characters. For SEO, keeping slugs under 75 characters is a common recommendation. Set a max length if your publishing platform requires one.

Slug Generator - Convert Text to URL Slug

What makes a good URL slug?

A well-formed URL slug is short, descriptive, and contains only lowercase letters, numbers, and hyphens. It should reflect the content of the page. Search engines use the slug as a relevance signal, and users see it in the browser address bar and in shared links.

Use hyphens, not underscores (Google treats hyphens as word separators).
Keep it under 75 characters when possible; long slugs get truncated in SERPs.
Remove stop words ("a", "the", "and") unless they are meaningful.
Avoid special characters, accents, and non-ASCII characters without transliteration.

Transliteration: handling accented characters

Accented characters like é, ñ, ü, and ç are technically valid in URLs (they are percent-encoded by browsers) but they create ugly, hard-to-share links. Transliteration converts them to their closest ASCII equivalent: "café" -> "cafe", "jalapeño" -> "jalapeno", "straße" -> "strasse". Enable transliteration (it is on by default) to produce clean, universally shareable slugs.

Separator choice

For public-facing URLs (blog posts, product pages, landing pages), use a hyphen (-). Underscores (_) are common in file systems and Python package names. Dots (.) are occasionally used in versioned documentation paths. All three options produce valid URLs.

Max length

Many content management systems impose a slug length limit. WordPress defaults to 200 characters; Shopify trims at 255. For SEO best practice, keep slugs under 75 characters. Enable the max length option to truncate automatically. The tool never cuts in the middle of a word.

CMS behavior differences

Platform	Max slug length	Auto-generation
WordPress	200 characters	Generated from post title on save
Shopify	255 characters	Generated from product title; editable
Next.js	No built-in limit	Manual - developer defines slug generation logic
Ghost CMS	191 characters	Generated from post title; editable
Contentful	256 characters	No auto-generation; set manually

Dynamic slug generation (JavaScript)

To generate slugs programmatically in JavaScript or TypeScript:

const slugify = (text) =>
  text.toLowerCase().replace(/\s+/g, '-').replace(/[^a-z0-9-]/g, '');

For production use with accented characters, consider the slugify npm package or a Unicode-aware transliteration library.

Unique slug strategies

When a slug already exists (e.g., a second blog post titled "My Vacation"), avoid collisions with one of these strategies:

Auto-increment suffix: append -2, -3, etc. (e.g., WordPress behavior). Simple and predictable.
UUID fragment: append the first 8 characters of a UUID (e.g., my-vacation-a3f2c1b4). Guaranteed unique but less readable.
Date prefix: prepend the publish date (2025-06-my-vacation). Works well for news sites where articles share titles on different dates.