Convert UTF8 Email Address

convert_utf8_email_address.php

if (!function_exists('convert_utf8_email_address')) {
    /**
     * To maintain compatibility with older systems, Amazon SES honors the 7-bit ASCII limitation
     * of SMTP as defined in RFC 2821. If you want to send content that contains non-ASCII
     * characters, you must encode those characters into a format that uses
     * 7-bit ASCII characters.
     *
     * @see https://docs.aws.amazon.com/ses/latest/dg/send-email-raw.html#send-email-mime-encoding-addresses
     */
    function convert_utf8_email_address(string $emailAddress): string {
        if (\Illuminate\Support\Facades\Validator::make(['email' => $emailAddress], ['email' => 'email'])->fails()) {
            return $emailAddress;
        }

        [$from, $domain] = explode('@', $emailAddress, limit: 2);

        /**
         * We need to convert the local part of the email address
         * using MIME encoded-word syntax.
         */
        $from = mb_encode_mimeheader($from, mb_detect_encoding($from));

        /**
         * We need to convert the domain part of the email address
         * using Punycode (RFC 3492).
         */
        $domain = idn_to_ascii($domain, IDNA_NONTRANSITIONAL_TO_ASCII, INTL_IDNA_VARIANT_UTS46);

        return sprintf('%s@%s', $from, $domain);
    }
}

pest.php

<?php

test('it_converts_utf8_email_address', function () {
  expect(convert_utf8_email_address('thomâs.müller@groß.de'))->toBe('[email protected]');
  expect(convert_utf8_email_address('thomas.muller@groß.de'))->toBe('[email protected]');
  expect(convert_utf8_email_address('thomâs.mü[email protected]'))->toBe('[email protected]');
});

test('it_doesnt_convert_ascii_email_address', function () {
  expect(convert_utf8_email_address('[email protected]'))->toBe('[email protected]');
});

Platform
Laravel

How to use
Copy/paste this snippet inside helpers.php