A slug is the human-readable part of a URL that identifies a specific page — for example, the how-to-write-a-slug in example.com/blog/how-to-write-a-slug.
Good slugs are lowercase, use hyphens instead of spaces, drop accents and special characters, and are short. They help both readers and search engines understand a page.
Turn any title into a clean slug with the slug generator.
What a slug is
A slug is the human-readable part of a URL that identifies a specific page — the "what-is-a-url-slug" at the end of this one. It replaces an opaque database identifier with something a person can read, remember, and understand before clicking. The name comes from newsroom jargon, where a slug was the short label given to a story in production.
What makes a good one
Lowercase throughout, because URL paths are case-sensitive on most servers and a capital letter creates a second address for the same page. Hyphens between words rather than underscores, which Google has long treated as word separators while underscores join words together. Accents removed and converted to their ASCII equivalents, since encoded characters turn a readable slug into a wall of percent signs. Short and descriptive, keeping the words that carry meaning and dropping filler. And stable, because a slug is a public address.
Changing a slug breaks things
Once a URL is published it is referenced by other sites, bookmarked, shared in messages and indexed by search engines. Changing the slug breaks all of those unless a redirect is left behind. If a slug must change, a 301 from the old address to the new one preserves both the visitors and the accumulated search ranking. Repeated slug changes without redirects are one of the more effective ways to lose traffic you already had.
Uniqueness
Two articles can legitimately share a title, so slugs need a tiebreaker — commonly a numeric suffix, a date segment, or a category prefix. Deciding this before publishing matters, because the alternative is discovering the collision after both URLs are live and having to change one of them.
Slugs and diacritics
Romanian, Turkish, Polish and many other languages routinely produce titles containing characters that must be percent-encoded in a URL. A single accented character can become several escape sequences, so a short title becomes an unreadable address that breaks when pasted into plain-text contexts. Transliterating to ASCII first keeps the slug readable and portable.