Pattern

Regex for URL slug

Lowercase URL slug — letters, digits, hyphens.

The URL slug regex is ^[a-z0-9]+(?:-[a-z0-9]+)*$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^[a-z0-9]+(?:-[a-z0-9]+)*$

Try in explainer → Download cheat sheet ↓

What it matches

my-blog-post
hello-world
seo-friendly-url-2024

What it doesn't match

My-Blog-Post
my_blog_post
-leading-dash
trailing-dash-

Notes & gotchas

No leading/trailing/consecutive hyphens. Lowercase letters and digits only. Used for SEO-friendly URLs.

Code in your language

Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.

Open in explainer →

Token-by-token breakdown

Every part of the pattern, left to right:

Token	Meaning
`^`	start of string (or line in multiline mode)
`[a-z0-9]+`	one or more: any of: lowercase letters, digits
`(?:`	start of a non-capturing group
`-`	literal text “-”
`[a-z0-9]+`	one or more: any of: lowercase letters, digits
`)*`	end of group, zero or more
`$`	end of string (or line in multiline mode)

About this pattern

Identifying and validating user identity (names, contact info, IDs) is one of the most common reasons developers reach for regex. The pattern below handles the format check; for full validation always confirm against a source of truth (database, API, or document).

Quick usage in different languages

This exact pattern — with the correct escaping and idioms for each language:

JavaScript: /^[a-z0-9]+(?:-[a-z0-9]+)*$/.test(value)
Python: re.match(r"^[a-z0-9]+(?:-[a-z0-9]+)*$", value)
Java: Pattern.compile("^[a-z0-9]+(?:-[a-z0-9]+)*$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^[a-z0-9]+(?:-[a-z0-9]+)*$")
Go: regexp.MustCompile(`^[a-z0-9]+(?:-[a-z0-9]+)*$`).MatchString(value)
Ruby: /^[a-z0-9]+(?:-[a-z0-9]+)*$/.match?(value)
PHP: preg_match('~^[a-z0-9]+(?:-[a-z0-9]+)*$~', $value)

The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.

Common pitfalls

Anchored to the whole string. This pattern uses ^ and $, so it requires the entire input to match. To find it inside a longer text, drop the anchors and use the global (g) flag.
Lowercase only. Ranges like [a-z] won't match uppercase. Add A-Z (or the i flag) if uppercase input should be accepted.
Watch for backtracking. This pattern nests quantifiers; on adversarial input that can cause exponential backtracking (ReDoS). Test with long non-matching strings, or use an RE2-based engine.
Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the url slug against a source of truth (database, API, or checksum) where it matters.

Related patterns

More patterns in the Identity & contact category: