Using PHPMailer to Send Mail through PHP

You want to send mail through PHP, but PHP’s built-in mail() function doesn’t support authenticated SMTP (Simple Mail Transfer Protocol), and cPanel mail servers require authentication for outgoing mail. PHPMailer solves that problem: it is a popular, actively maintained, open-source library that adds authenticated SMTP, attachments, and HTML formatting to outgoing mail from your PHP code. This guide walks through a working example you can adapt for local development or a live InMotion Hosting account.

The sample script targets PHPMailer’s current namespaced 6.x and 7.x classes (PHPMailer\PHPMailer\PHPMailer), not the older class.phpmailer.php file.

Note: Download the current release of PHPMailer from its GitHub repository, or install it with Composer as shown next. Learn more about InMotion Hosting’s PHP hosting plans.

Install the PHPMailer Dependencies

Composer is the recommended way to add PHPMailer to your project. It downloads the library, resolves its dependencies, and generates the autoloader your script needs, all with one command. Run this from your project’s root directory:

composer require phpmailer/phpmailer

Composer creates a vendor/ directory and a vendor/autoload.php file. Require that file at the top of your script and every class PHPMailer needs becomes available automatically.

If you cannot use Composer, download the latest release from PHPMailer’s GitHub repository instead, and require src/Exception.php, src/PHPMailer.php, and src/SMTP.php directly from the extracted archive.

Add the Code to Send Mail through PHP

Before you run the script, change the example values in the table to match your own sender, recipient, and mail server details.

Not sure what to put in the host, port, or username fields? Those are the same settings you would enter in an email client. See how to find your email settings in cPanel or Webmail to look them up. On an InMotion Hosting cPanel account, the username is always the mailbox’s full email address, and the recommended outgoing setting is SMTP port 465 with SSL/TLS. To use that port instead of the sample’s port 587, set Port to 465 and SMTPSecure to PHPMailer::ENCRYPTION_SMTPS.

Local development: Leave $developmentMode set to true. The script then prints the full SMTP conversation and relaxes certificate checks, which is normal for a local server with a self-signed certificate.

Live server: Set $developmentMode to false before you deploy. The script then hides the SMTP transcript and enforces normal certificate validation, which is what you want once mail goes out to real recipients.

<?php
require "vendor/autoload.php";

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

$developmentMode = true;

$mailer = new PHPMailer(true);

try {
    $mailer->SMTPDebug = $developmentMode ? SMTP::DEBUG_SERVER : SMTP::DEBUG_OFF;
    $mailer->isSMTP();

    if ($developmentMode) {
        $mailer->SMTPOptions = [
            'ssl' => [
                'verify_peer' => false,
                'verify_peer_name' => false,
                'allow_self_signed' => true,
            ],
        ];
    }

    $mailer->Host = 'mail.example.com';
    $mailer->SMTPAuth = true;
    $mailer->Username = '[email protected]';
    $mailer->Password = 'password';
    $mailer->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mailer->Port = 587;

    $mailer->setFrom('[email protected]', 'Name of sender');
    $mailer->addAddress('[email protected]', 'Name of recipient');

    $mailer->isHTML(true);
    $mailer->Subject = 'PHPMailer Test';
    $mailer->Body = 'This is a <b>SAMPLE</b> email sent through <b>PHPMailer</b>';

    $mailer->send();
    echo "MAIL HAS BEEN SENT SUCCESSFULLY";
} catch (Exception $e) {
    echo "EMAIL SENDING FAILED. INFO: " . $mailer->ErrorInfo;
}

A note about the closing PHP tag

PHP does not require a closing ?> tag at the end of a file, and the script above leaves it out on purpose. The PHP manual recommends omitting it, because accidental whitespace or a new line after the tag sends output early, which is a classic cause of the “headers already sent” error. Two situations call for different handling:

Pure PHP file: Omit the closing tag completely, exactly as the sample above does.

<?php
require "vendor/autoload.php";
// PHP code continues to the end of the file

PHP mixed with HTML or other markup: Add ?> right before the HTML begins, then omit the closing tag again at the end of the file.

<?php
require "vendor/autoload.php";
// PHP code
?>
<html>
  <body>
    <p>Message sent.</p>
  </body>
</html>

If the Message Does Not Send

If the script prints “EMAIL SENDING FAILED. INFO: …” instead of the success message, PHPMailer threw an exception because something in the send failed. Set $developmentMode to true temporarily so PHPMailer prints the full SMTP transcript instead of the generic error message. Most failures trace back to an incorrect host, port, username, or password, so check those values against your mailbox’s settings first. If the connection itself fails or times out, work through why won’t my PHP app send mail? next.

Save the script, upload it to your server, and load it in a browser. A successful run prints “MAIL HAS BEEN SENT SUCCESSFULLY” and hands the message to your mail server for delivery. If you only need to send a simple message without SMTP authentication, compare this approach with PHP’s built-in mail() function.