Validate Email Address in PHP

Functions:

The functions below are used to validate an email address in PHP.

<?php //validate email address functions

//simple regex
function simpleValidEmail($email)
{
	$pattern = "/[a-zA-Z0-9_\-.+]+@[a-zA-Z0-9-]+.[a-zA-Z]+/";
	if(preg_match($pattern, $email))
		return true;
	else
		return false;
}

//advanced regex from PHP source
function advancedValidEmail($email)
{
	$pattern = '/^(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){255,})(?!(?:(?:\\x22?\\x5C[\\x00-\\x7E]\\x22?)|(?:\\x22?[^\\x5C\\x22]\\x22?)){65,}@)(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22))(?:\\.(?:(?:[\\x21\\x23-\\x27\\x2A\\x2B\\x2D\\x2F-\\x39\\x3D\\x3F\\x5E-\\x7E]+)|(?:\\x22(?:[\\x01-\\x08\\x0B\\x0C\\x0E-\\x1F\\x21\\x23-\\x5B\\x5D-\\x7F]|(?:\\x5C[\\x00-\\x7F]))*\\x22)))*@(?:(?:(?!.*[^.]{64,})(?:(?:(?:xn--)?[a-z0-9]+(?:-+[a-z0-9]+)*\\.){1,126}){1,}(?:(?:[a-z][a-z0-9]*)|(?:(?:xn--)[a-z0-9]+))(?:-+[a-z0-9]+)*)|(?:\\[(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){7})|(?:(?!(?:.*[a-f0-9][:\\]]){7,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,5})?)))|(?:(?:IPv6:(?:(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){5}:)|(?:(?!(?:.*[a-f0-9]:){5,})(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3})?::(?:[a-f0-9]{1,4}(?::[a-f0-9]{1,4}){0,3}:)?)))?(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))(?:\\.(?:(?:25[0-5])|(?:2[0-4][0-9])|(?:1[0-9]{2})|(?:[1-9]?[0-9]))){3}))\\]))$/iD';

	return (bool) preg_match($pattern, $email);
}

//built in PHP function only available in PHP 5.2 or newer
//uses the regex found in the above advancedValidEmail function
filter_var($emailaddress, FILTER_VALIDATE_EMAIL);
?>

The filter_var function shown above can be used to filter and validate many other things that can be seen on the PHP Types of Filters page. The filter_var function function is only available in PHP 5.2 or newer.

NOTE: The regex used in the advancedValidEmail function is from the PHP filter_var source and contains the following copyright from Michael Rushton. As stated: “Feel free to use and redistribute this code. But please keep this copyright notice.”

Example Usage:

<?php //example usage for email validation functions

$emailaddress = '[email protected]'; //example email

//example usage of the advancedValidEmail function
if (advancedValidEmail($emailaddress))
{
	echo($emailaddress."is a valid email for advancedValidEmail &lt;br/&gt;");
}

//example usage of the simpleValidEmail function
if (simpleValidEmail($emailaddress))
{
	echo($emailaddress."is a valid email for simpleValidEmail &lt;br/&gt;");
}

//example usage of the filter_var function
if (filter_var($emailaddress, FILTER_VALIDATE_EMAIL))
{
	echo($emailaddress."is a valid email for filter_var &lt;br/&gt;");
}
?>

Results:

[email protected] a valid email for simpleValidEmail 
[email protected] a valid email for advancedValidEmail 
[email protected] a valid email for filter_var