Email with Plus Addressing Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching email with plus addressing, ported and verified for PHP. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// Email with Plus Addressing
// ReDoS-safe | RegexVault — Web & Network > Misc

define('EMAIL_WITH_PLUS_ADDRESSING_PATTERN', '/^([a-zA-Z0-9.!#$%&\'*\/=?^_`{|}~\-]{1,64})\+([a-zA-Z0-9.\-_]{1,64})@([a-zA-Z0-9](?:[a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?)*)$/');

function validate_email_with_plus_addressing(string $input): bool {
    return (bool) preg_match(EMAIL_WITH_PLUS_ADDRESSING_PATTERN, $input);
}

// Example
var_dump(validate_email_with_plus_addressing("user+tag@example.com")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > Misc category and carries a ReDoS-safe certification. That matters for PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. 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

Capture group 1: local base, group 2: plus tag, group 3: domain. Use to detect sub-addressing and optionally strip the tag before lookup. Gmail, Outlook, and Fastmail support plus addressing.