How to Send Email from PHP with SMTP (PHPMailer)

Applies to: PHPMailer 7 with PHP 8.1 or later (cPanel hosting, VPS and dedicated servers)

PHP’s built-in mail() function sends without logging in, so the mail often lands in spam or isn’t sent at all. Sending through an SMTP account with a login is far more reliable. PHPMailer is the most widely used PHP library for that. We tested the example below with PHPMailer 7.1.1.

1. Install PHPMailer with Composer

cd /path/to/your/site
composer require phpmailer/phpmailer

On cPanel hosting, run it over SSH in your site’s folder.

2. Send a message

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

$mail = new PHPMailer(true);
try {
    $mail->isSMTP();
    $mail->Host       = 'mail.example.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = 'website@example.com';
    $mail->Password   = getenv('SMTP_PASSWORD');   // keep it out of the code
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;  // port 465; or ENCRYPTION_STARTTLS with port 587
    $mail->Port       = 465;

    $mail->setFrom('website@example.com', 'Example Website');
    $mail->addAddress('customer@example.net');
    $mail->addReplyTo('info@example.com');
    $mail->Subject = 'Thanks for your message';
    $mail->Body    = 'We received your message and will reply soon.';

    $mail->send();
    echo 'sent';
} catch (Exception $e) {
    echo 'failed: ' . $mail->ErrorInfo;
}

Settings to get right

• Username and From: use a real mailbox on your domain and send from that address. Put visitors’ addresses in Reply-To, never in From.
• Port: 465 with SMTPS or 587 with STARTTLS; see SMTP port numbers.
• SPF and DKIM for the domain, so the mail isn’t marked as spam: cPanel Email Deliverability.
• Debugging: add $mail->SMTPDebug = 2; temporarily to see the conversation with the server.

WordPress

WordPress already includes PHPMailer. Use an SMTP plugin to send through your mailbox instead of writing code.