URL Slug Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching url slug, ported and verified for JavaScript. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// URL Slug
// ReDoS-safe | RegexVault — Web & Network > URL

const urlSlugRegex = /^[a-z0-9](?:[a-z0-9\-]{0,98}[a-z0-9])?$/;

function validateUrlSlug(input: string): boolean {
  return urlSlugRegex.test(input);
}

// Example
console.log(validateUrlSlug("hello-world")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > URL category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Maximum length 100 chars enforced by the {0,98} bound. This pattern does not enforce no-consecutive-hyphens by default. To reject double hyphens, add a negative lookahead: (?!.*--) after the ^.