How to Validate an Email with PHP

This tutorial shows the safest and simplest ways to validate an Email with PHP.

A. Using the filter_var() Method

The first way to check if an email is well-formed is by using the filter_var() function.

In case the email is not well-formed, an error will be shown by the function, like here:

$email = test_input($_POST["email"]);
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
  $emailErr = "Invalid email format";

B. Using the preg_match() Method

Another way of email validation is by using the preg_match() regular expression.


   $email = "";

   if(preg_match("~([a-zA-Z0-9!#$%&'*+-/=?^_`{|}~])@([a-zA-Z0-9-]).([a-zA-Z0-9]{2,4})~", $email))
       echo 'This is a valid email.';
       echo 'This is an invalid email.';

Describing the PHP filter_var() Function

This PHP function is aimed at validating and sanitizing data. It is capable of filtering a single variable with a particular filter. Two pieces of data are included in it: the variable, which should be checked, and the way of checking to apply.

Describing the preg_match() Regex

The preg_match() regular expression is aimed at searching the string for a pattern. True will be returned when the pattern is there, and, otherwise, false.

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