What Is a URL Slug? SEO Best Practices

Every good URL has a readable, descriptive ending — the part that tells you what the page is about. That part is called the slug, and getting it right is a small but genuine SEO and usability win. This guide explains what slugs are and the rules for writing them well.

What exactly is a slug?

The slug is the human-readable portion of a URL that identifies a specific page. In this address:

https://example.com/blog/how-to-write-clean-urls
                         ↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑
                         this is the slug

The term comes from journalism, where a "slug" was a short label for a story in progress. A good slug describes the page in a few words; a bad one is a string of numbers or random characters.

Why slugs matter

• For users: a clean slug tells people what they will get before they click, and it looks trustworthy when shared. Compare /article?id=8821 with /how-to-bake-bread — one inspires confidence, the other does not.
• For search engines: Google reads the words in a slug as a signal of the page's topic, and a matching slug appears in bold in search results, subtly improving clicks.
• For sharing: a descriptive slug becomes meaningful anchor text when someone pastes the bare URL into a forum or chat.

The rules for a good slug

1. Use lowercase. URLs can be case-sensitive on some servers, so mixed case risks creating accidental duplicate pages. Stick to lowercase always.
2. Separate words with hyphens, not underscores. Google treats hyphens as word separators but historically did not treat underscores that way. So clean-urls reads as two words; clean_urls may read as one.
3. Remove accents and special characters. Transliterate café to cafe. Special characters get percent-encoded into ugly, unreadable strings.
4. Keep it short. Include the key words and drop filler like "a", "the", and "of". how-to-format-json beats a-complete-guide-to-how-you-can-format-your-json.
5. Make it stable. Once a page is published and linked, changing its slug breaks those links unless you set up a redirect. Choose well the first time.

Slugs and keywords

It is good practice to include your target keyword in the slug, because it reinforces the topic for both users and search engines. But do not stuff keywords — cheap-shoes-buy-shoes-discount-shoes looks spammy and helps nobody. One clear, descriptive phrase is the goal.

Generating slugs automatically

Most content systems generate a slug from your title automatically, but the results are not always clean — especially with accented characters, punctuation, or very long titles. The generator below converts any title into a proper slug: lowercase, hyphen-separated, accent-free, and ready to use. Paste a headline and copy a URL-safe slug in one click.