MAC Address (Colon-Separated, Case-Insensitive) Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching mac address (colon-separated, case-insensitive), 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

// MAC Address (Colon-Separated, Case-Insensitive)
// ReDoS-safe | RegexVault — Web & Network > MAC Address

const macAddressColonseparatedCaseinsensitiveRegex = /^[0-9a-fA-F]{2}(?::[0-9a-fA-F]{2}){5}$/;

function validateMacAddressColonseparatedCaseinsensitive(input: string): boolean {
  return macAddressColonseparatedCaseinsensitiveRegex.test(input);
}

// Example
console.log(validateMacAddressColonseparatedCaseinsensitive("00:1A:2B:3C:4D:5E")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > MAC Address 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

Preferred for input validation where user-submitted MAC addresses may be in mixed case. Normalize to lowercase before storage.