How to Send Email using PHP mail() Function

What is PHP mail?

PHP mail is the built-in PHP function that is used to send emails from PHP scripts.

The mail function accepts the following parameters:

• Email address
• Subject
• Message
• CC or BCC email addresses

Why and When to use PHP mail

The mail function is useful in many situations:

• It is a cost effective way of notifying users of important events.
• Let users contact you via email by providing a contact us form on the website that emails the provided content.
• Developers can use it to receive system errors by email.
• You can use it to email your newsletter subscribers.
• You can use it to send password reset links to users who forget their passwords.
• You can use it to email activation and confirmation links. This is useful when registering users and verifying their email addresses.

Sending mail using PHP

The PHP mail function has the following basic syntax.

<?php
mail($to_email_address,$subject,$message,[$headers],[$parameters]);
?>

HERE,

• “$to_email_address” is the email address of the mail recipient
• “$subject” is the email subject
• “$message” is the message to be sent.
• “[$headers]” is optional; it can be used to include information such as CC and BCC.
  • CC is the acronym for carbon copy. It is used when you want to send a copy to an interested person, i.e. a complaint email sent to a company can also be sent as CC to the complaints board.
  • BCC is the acronym for blind carbon copy. It is similar to CC, but the email addresses included in the BCC section are not shown to the other recipients.

Simple Mail Transmission Protocol (SMTP)

PHP mail uses the Simple Mail Transmission Protocol (SMTP) to send mail.

On a hosted server, the SMTP settings would already have been set.

The SMTP mail settings can be configured from the “php.ini” file in the PHP installation folder.

To configure SMTP settings on your localhost, assuming you are using XAMPP on Windows, locate the “php.ini” file in the directory “C:\xampp\php”.

• Open it using Notepad or any text editor. We will use Notepad in this example. Click on the Edit menu.

• Click on the Find… menu

• The Find dialog will appear

• Click on the Find Next button

Locate the entries under [mail function]. The default lines usually look like this:

• ; SMTP = localhost
• ; smtp_port = 25

Remove the semicolons before SMTP and smtp_port, and set SMTP to your SMTP server and the port to your SMTP port. Your settings should look as follows:

• SMTP = smtp.example.com
• smtp_port = 25

Note: the SMTP settings can be obtained from your web hosting provider. If the server requires authentication, then add the following lines:

• auth_username = example_username@example.com
• auth_password = example_password

Save the new changes and restart the Apache server.

PHP Mail Example

Let us now look at an example that sends a simple mail.

<?php
$to_email = 'name@example.com';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail function';
$headers = 'From: noreply@example.com';
mail($to_email,$subject,$message,$headers);
?>

Output:

Note: the above example only takes the 4 mandatory parameters. You should replace the above fictitious email address with a real email address.

Sanitizing email user inputs

The above example uses hard coded values in the source code for the email address and other details for simplicity.

Let us assume you have to create a contact us form where users fill in the details and then submit.

• Users can accidentally or intentionally inject code in the headers, which can result in sending spam mail.
• To protect your system from such attacks, you can create a custom function that sanitizes and validates the values before the mail is sent.

Let us create a custom function that validates and sanitizes the email address using the filter_var built-in function. The filter_var function is used to sanitize and validate user input data.

It has the following basic syntax.

<?php
filter_var($field, SANITIZATION_TYPE);
?>

HERE,

• “filter_var(…)” is the validation and sanitization function
• “$field” is the value of the field to be filtered.
• “SANITIZATION_TYPE” is the type of sanitization to be performed on the field, such as:
  • FILTER_VALIDATE_EMAIL – returns true for valid email addresses and false for invalid email addresses.
  • FILTER_SANITIZE_EMAIL – removes illegal characters from email addresses, so an address with stray characters is reduced to info@domain.com.
  • FILTER_SANITIZE_URL – removes illegal characters from URLs, leaving a clean address such as https://www.example.com.
  • FILTER_SANITIZE_STRING – removes tags from string values, so <b>am bold</b> becomes am bold. Note this filter is deprecated in PHP 8.1; use htmlspecialchars() instead.

The code below uses a custom function to send secure mail.

<?php
function sanitize_my_email($field) {
$field = filter_var($field, FILTER_SANITIZE_EMAIL);
if (filter_var($field, FILTER_VALIDATE_EMAIL)) {
return true;
} else {
return false;
}
}
$to_email = 'name@example.com';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail function';
$headers = 'From: noreply@example.com';
// check if the email address is invalid
$secure_check = sanitize_my_email($to_email);
if ($secure_check == false) {
echo "Invalid input";
} else { // send email
mail($to_email, $subject, $message, $headers);
echo "This email is sent using PHP Mail";
}
?>

Output:

Secure Mail

Emails can be intercepted during transmission by unintended recipients.

This can expose the contents of the email to unintended recipients.

Secure mail solves this problem by transmitting emails over an encrypted connection using SSL or TLS, for example SMTP over SSL on port 465 or STARTTLS on port 587.

Encryption scrambles the message before sending it, so only the intended recipient’s mail server can read it.

PHPMailer: A Better Alternative to mail()

For real applications, most developers use the PHPMailer library instead of the raw mail() function. PHPMailer authenticates with an external SMTP server, which greatly improves deliverability, and it makes attachments and HTML email simple.

Install it with Composer, then send mail through an authenticated, encrypted SMTP connection as shown below.

<?php
use PHPMailer\PHPMailer\PHPMailer;
require 'vendor/autoload.php';

$mail = new PHPMailer(true);
$mail->isSMTP();
$mail->Host = 'smtp.example.com';
$mail->SMTPAuth = true;
$mail->Username = 'user@example.com';
$mail->Password = 'secret';
$mail->SMTPSecure = 'tls';
$mail->Port = 587;

$mail->setFrom('noreply@example.com', 'My App');
$mail->addAddress('name@example.com');
$mail->Subject = 'Testing PHPMailer';
$mail->Body = 'This email is sent using PHPMailer over SMTP';
$mail->send();
?>

Compared with mail(), PHPMailer gives you SMTP authentication, built-in encryption, attachment support, and clearer error handling, which is why it is the recommended choice for production email.

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