Every URL you publish is either working for you or against you. Most developers get this right by default — lowercase, hyphens, no garbage parameters. But many sites still publish URLs like /post?id=8472 or /blog/2026/06/14/untitled-draft-final-v3. This guide covers getting it right the first time.
What Is a URL Slug?
The slug is the human-readable part of a URL that identifies a specific page. In:
``
https://snappytools.app/keyword-density-checker/
`
The slug is keyword-density-checker.
A well-formed slug is lowercase, uses hyphens to separate words, and contains only the words that matter — no filler, no punctuation, no auto-generated noise.
Why Slugs Matter for SEO
Google reads URLs as a ranking signal. A slug that matches your target keyword tells the crawler what the page is about before it even reads the content.
More importantly: URLs appear in search results. A clean slug like /how-to-write-a-cover-letter/ tells the user what they'll get before they click. A messy slug like /p/46173 tells them nothing. Click-through rates reflect this.
Three rules:
- Match the slug to your page's primary keyword phrase
- Use hyphens, never underscores — Google treats underscores as word joiners: my_page
reads as mypage - Remove stop words (a, an, the, and, or) unless they're essential to meaning
Common Mistakes
Too long: /how-i-discovered-that-the-best-approach-to-writing-short-urls-is-to-remove-unnecessary-words/
Keep slugs under 5–6 words where possible.
Dates in URLs: /blog/2026/06/14/my-post/
Dates signal that content is old — even when the information is still current. Skip the date for evergreen content.
Keyword stuffing: /free-best-online-keyword-density-tool-seo-checker-2026/
One clear keyword phrase per slug.
Spaces encoded as %20: /my%20blog%20post/
Always replace spaces with hyphens.
Generate Slugs in Code
The algorithm is simple:
`javascript
function slugify(text) {
return text
.toLowerCase()
.normalize('NFD')
.replace(/[̀-ͯ]/g, '')
.replace(/[^a-z0-9\s-]/g, '')
.trim()
.replace(/\s+/g, '-')
.replace(/-+/g, '-');
}
slugify("What Is a URL Slug? (Complete Guide)")
// → "what-is-a-url-slug-complete-guide"
`
With stop word removal:
`javascript
const STOP = new Set(['a','an','the','and','or','but','in','on','at','to','for','of','with','by','from','is','are']);
function slugifyClean(text) {
return text.toLowerCase().split(/\s+/)
.filter(w => !STOP.has(w))
.join('-')
.replace(/[^a-z0-9-]/g, '');
}
slugifyClean("What Is a URL Slug and Why Does It Matter")
// → "what-url-slug-why-does-matter"
``
Whether to strip stop words depends on the phrase. Test before deciding.
When to Update a Slug
Generally: don't. Changing a URL breaks incoming links and accumulated PageRank. If you must change it, set up a 301 redirect immediately.
Exception: if a slug contains a time-bound keyword ("best-tools-2024") and you update the page annually, change the slug and redirect from the old one.
Quick Checklist
- [ ] Lowercase only
- [ ] Hyphens as word separators
- [ ] Primary keyword included
- [ ] Stop words removed where they don't alter meaning
- [ ] Under 60 characters
- [ ] No dates unless content is time-sensitive
- [ ] No special characters
Tools That Help
If you're working on SEO-heavy content and want to check keyword usage across your copy, the SnappyTools Keyword Density Checker runs in-browser with no upload. Paste your content, enter your keyword, and get exact frequency counts and density percentage instantly.
Originally published at https://snappytools.app/keyword-density-checker/