Web & APIs · 4 min read
URL Slugs and SEO-Friendly URLs
The slug is the human-readable part of a URL — the how-to-make-bread in example.com/how-to-make-bread. It is a small detail that affects how your page reads in search results, how shareable the link feels, and how well people can guess what a page contains.
This guide covers what makes a slug good and the conventions worth following.
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What a good slug looks like
Lowercase, hyphen-separated, short, and descriptive. Strip accents and punctuation so the URL is safe everywhere, drop filler words that add no meaning, and keep the main keyword near the front. css-grid-guide beats the-complete-and-ultimate-guide-to-using-css-grid-in-2026.
Hyphens, not underscores
Search engines treat hyphens as word separators but underscores as joiners — so blue-widget reads as two words while blue_widget can be read as one. This is a long-standing, well-documented distinction, and it is why essentially every CMS generates hyphenated slugs.
Changing a slug later
Changing a published URL breaks every existing link and loses the ranking that URL has built. If you must change it, set up a 301 redirect from the old slug to the new one so links and search equity carry over. Better still, choose a slug that will not need to change — avoid embedding years or "new" in it.
Beyond the slug
Keep URL structure shallow and logical; deeply nested paths are harder to read and share. Use a canonical tag so that variations of a URL (with tracking parameters, for example) consolidate to one version, and keep campaign parameters off internal links.