<?php

// Example for a php function that checks the syntax of an email address
// and verifies online if the given domain belongs to an known provider
// of one-time email addresses and checks if at least one MX record exists

function check_email($email) {
	// set return value to 0 until the email address has been evaluated 
	$return = 0;
	// Check syntax of the given email address 
	if( (preg_match('/(@.*@)|(\.\.)|(@\.)|(\.@)|(^\.)/', $email)) || (preg_match('/^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,6}|[0-9]{1,3})(\]?)$/',$email)) ) 
		{
	// Extraxt domainname from given email address
		list(, $domain) = explode('@', $email);
		$domain = trim($domain);
		// Fill in your personal api key (see http://www.block-disposable-email.com/register.php)  
		$key     = '123abc';
		$request = 'http://check.block-disposable-email.com/api/json/'.$key.'/'.$domain; 
		if ($response = @file_get_contents($request))
			{
			$dea = json_decode($response);
			// Analyse the domain_status response only if the request_status was successful
			if ($dea->request_status == 'success')
				{
				if ($dea->domain_status == 'ok') $return = 1;
				if ($dea->domain_status == 'block') $return = 0;
				}
			// If MX checks fail also return 0
			elseif ($dea->request_status == 'fail_input_domain') $return = 0;
			// If the API query return some other response accept the given address anyway. 
			// Too high risk to lose one customer! 
			else $return = 1;
			}
		// Wenn Website down ist Registrierung auch zulassen
	// If the service is currently down and the api does not respond also accept the given email address
		else $return = 1;
	}
	return $return;
}

// Usage-Example:

$email2check = 'nobody@mailinator.com';
if (!check_email($email2check)) echo "The given address is not allowed to register!";
else echo "Welcome to XYZ...";

?>