International Phone with Formatting (Liberal) Regex for PHP

What this pattern does

This page provides a well-structured, multi-part regular expression for matching international phone with formatting (liberal), 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
// International Phone with Formatting (Liberal)
// ReDoS-safe | RegexVault — Localization > Phone Numbers

define('INTERNATIONAL_PHONE_WITH_FORMATTING_LIBERAL_PATTERN', '/^\+?[1-9][0-9]{0,2}[\s.()-]{0,2}[0-9][0-9\s.()-]{5,15}[0-9]$/');

function validate_international_phone_with_formatting_liberal(string $input): bool {
    return (bool) preg_match(INTERNATIONAL_PHONE_WITH_FORMATTING_LIBERAL_PATTERN, $input);
}

// Example
var_dump(validate_international_phone_with_formatting_liberal("+1 (212) 555-0100")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Localization > Phone Numbers 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

Liberal pattern for accepting phone numbers from international forms. Strip all non-digits except leading + before storing. Normalize to E.164 for storage and comparison.