Gmail Address with Canonical Normalization Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching gmail address with canonical normalization, ported and verified for JavaScript. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. 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

// Gmail Address with Canonical Normalization
// ReDoS-safe | RegexVault — Identity & PII > Email Address

const gmailAddressWithCanonicalNormalizationRegex = /^[a-zA-Z0-9]+(\.[a-zA-Z0-9]+)*(?:\+[^@]*)?@(gmail\.com|googlemail\.com)$/i;

function validateGmailAddressWithCanonicalNormalization(input: string): boolean {
  return gmailAddressWithCanonicalNormalizationRegex.test(input);
}

// Example
console.log(validateGmailAddressWithCanonicalNormalization("user@gmail.com")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Email 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

Gmail canonicalization: strip dots from local part, strip everything from + to @ inclusive, lowercase. u.s.e.r+tag@gmail.com and user@gmail.com deliver to the same inbox. Also, googlemail.com is an alias for gmail.com.