Content-Type MIME Type Regex for PHP

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching content-type mime type, 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
// Content-Type MIME Type
// ReDoS-checked | RegexVault — Web & Network > HTTP

define('CONTENTTYPE_MIME_TYPE_PATTERN', '/^[a-zA-Z][a-zA-Z0-9!#$&\-^_]{0,59}\/[a-zA-Z][a-zA-Z0-9!#$&\-^_.+]{0,59}(?:;\s*[a-zA-Z][a-zA-Z0-9\-]{0,49}=[^;\s]{1,100})*$/');

function validate_contenttype_mime_type(string $input): bool {
    return (bool) preg_match(CONTENTTYPE_MIME_TYPE_PATTERN, $input);
}

// Example
var_dump(validate_contenttype_mime_type("application/json")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > HTTP category and has been checked for ReDoS risk. 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

Parameters use name=value format separated by semicolons. The charset parameter is the most common. IANA maintains the media type registry.