PHP Code Example for mySMTP with PHPMailer

Use PHPMailer or Symfony Mailer to send transactional and marketing email from PHP through mySMTP. Both libraries support TLS encryption and SMTP authentication.

Prerequisites

PHP 8.1 or later
Composer
Your mySMTP username and password from the setup email
Your mySMTP hostname from the setup email (shown as relayxx.mysmtp.com in these examples)

PHPMailer via Composer

Install

composer require phpmailer/phpmailer

Basic send example

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

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

$mail = new PHPMailer(true);

try {
    $mail->isSMTP();
    $mail->Host       = getenv('MYSMTP_HOST') ?: 'relayxx.mysmtp.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv('MYSMTP_USER');
    $mail->Password   = getenv('MYSMTP_PASS');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    $mail->setFrom('you@yourdomain.com', 'Your Name');
    $mail->addAddress('recipient@example.com', 'Recipient Name');
    $mail->isHTML(false);
    $mail->Subject = 'Test email from PHPMailer';
    $mail->Body    = 'This is a plain text test message sent through mySMTP.';

    $mail->send();
    echo 'Message sent successfully';
} catch (Exception $e) {
    echo 'Message could not be sent. Error: ', $mail->ErrorInfo;
}

Replace relayxx.mysmtp.com with your real hostname from the mySMTP setup email. Load credentials from environment variables, never hardcode them in source files.

HTML body with attachment

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

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

$mail = new PHPMailer(true);

try {
    $mail->isSMTP();
    $mail->Host       = getenv('MYSMTP_HOST') ?: 'relayxx.mysmtp.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv('MYSMTP_USER');
    $mail->Password   = getenv('MYSMTP_PASS');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    $mail->setFrom('you@yourdomain.com', 'Your Name');
    $mail->addAddress('recipient@example.com');
    $mail->addReplyTo('you@yourdomain.com');
    $mail->isHTML(true);
    $mail->Subject = 'HTML email with attachment';
    $mail->Body    = '<h1>Hello</h1><p>This is an HTML message.</p>';
    $mail->AltBody = 'Hello. This is a plain text fallback.';

    $mail->addAttachment('/path/to/invoice.pdf', 'invoice.pdf');

    $mail->send();
    echo 'Message sent successfully';
} catch (Exception $e) {
    echo 'Error: ', $mail->ErrorInfo;
}

Symfony Mailer DSN

If you use Symfony, configure the mailer DSN in .env or config/packages/mailer.yaml:

MAILER_DSN=smtp://USERNAME:PASSWORD@relayxx.mysmtp.com:587

Replace USERNAME, PASSWORD, and relayxx.mysmtp.com with your actual credentials and hostname from the setup email. Symfony Mailer uses STARTTLS automatically on port 587.

Error handling

Always wrap PHPMailer calls in a try/catch block. Exception is thrown for SMTP connection failures, authentication errors, and rejected recipients. Inspect $mail->ErrorInfo for the exact server response.

Common errors

535 Authentication failed

Your username or password is incorrect, or your account is not yet activated. Re-enter credentials exactly as shown in the setup email. See Setting up SMTP credentials.

Connection timeout or refused

Your network or host may block port 587. Try port 2525 with STARTTLS, or port 465 with PHPMailer::ENCRYPTION_SMTPS. See Supported SMTP ports and encryption.

TLS handshake failure

The encryption setting does not match the port. Use ENCRYPTION_STARTTLS for ports 587 and 2525. Use ENCRYPTION_SMTPS for port 465.

Test your SPF, DKIM, and DMARC setup with the mySMTP Deliverability Toolbox before sending large volumes.

Use PHPMailer or Symfony Mailer to send transactional and marketing email from PHP through mySMTP. Both libraries support TLS encryption and SMTP authentication.

Prerequisites

PHP 8.1 or later
Composer
Your mySMTP username and password from the setup email
Your mySMTP hostname from the setup email (shown as relayxx.mysmtp.com in these examples)

PHPMailer via Composer

Install

composer require phpmailer/phpmailer

Basic send example

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

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

$mail = new PHPMailer(true);

try {
    $mail->isSMTP();
    $mail->Host       = getenv('MYSMTP_HOST') ?: 'relayxx.mysmtp.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv('MYSMTP_USER');
    $mail->Password   = getenv('MYSMTP_PASS');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    $mail->setFrom('you@yourdomain.com', 'Your Name');
    $mail->addAddress('recipient@example.com', 'Recipient Name');
    $mail->isHTML(false);
    $mail->Subject = 'Test email from PHPMailer';
    $mail->Body    = 'This is a plain text test message sent through mySMTP.';

    $mail->send();
    echo 'Message sent successfully';
} catch (Exception $e) {
    echo 'Message could not be sent. Error: ', $mail->ErrorInfo;
}

Replace relayxx.mysmtp.com with your real hostname from the mySMTP setup email. Load credentials from environment variables, never hardcode them in source files.

HTML body with attachment

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

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

$mail = new PHPMailer(true);

try {
    $mail->isSMTP();
    $mail->Host       = getenv('MYSMTP_HOST') ?: 'relayxx.mysmtp.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv('MYSMTP_USER');
    $mail->Password   = getenv('MYSMTP_PASS');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    $mail->setFrom('you@yourdomain.com', 'Your Name');
    $mail->addAddress('recipient@example.com');
    $mail->addReplyTo('you@yourdomain.com');
    $mail->isHTML(true);
    $mail->Subject = 'HTML email with attachment';
    $mail->Body    = '<h1>Hello</h1><p>This is an HTML message.</p>';
    $mail->AltBody = 'Hello. This is a plain text fallback.';

    $mail->addAttachment('/path/to/invoice.pdf', 'invoice.pdf');

    $mail->send();
    echo 'Message sent successfully';
} catch (Exception $e) {
    echo 'Error: ', $mail->ErrorInfo;
}

Symfony Mailer DSN

If you use Symfony, configure the mailer DSN in .env or config/packages/mailer.yaml:

MAILER_DSN=smtp://USERNAME:PASSWORD@relayxx.mysmtp.com:587

Replace USERNAME, PASSWORD, and relayxx.mysmtp.com with your actual credentials and hostname from the setup email. Symfony Mailer uses STARTTLS automatically on port 587.

Error handling

Common errors

535 Authentication failed

Your username or password is incorrect, or your account is not yet activated. Re-enter credentials exactly as shown in the setup email. See Setting up SMTP credentials.

Connection timeout or refused

Your network or host may block port 587. Try port 2525 with STARTTLS, or port 465 with PHPMailer::ENCRYPTION_SMTPS. See Supported SMTP ports and encryption.

TLS handshake failure

The encryption setting does not match the port. Use ENCRYPTION_STARTTLS for ports 587 and 2525. Use ENCRYPTION_SMTPS for port 465.

Test your SPF, DKIM, and DMARC setup with the mySMTP Deliverability Toolbox before sending large volumes.

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API & Webhooks

PHP Code Example for mySMTP with PHPMailer

Prerequisites

PHPMailer via Composer

Install

Basic send example

HTML body with attachment

Error handling

Common errors

Prerequisites

PHPMailer via Composer

Install

Basic send example

HTML body with attachment

Error handling

Common errors

​Prerequisites

​PHPMailer via Composer

​Install

​Basic send example

​HTML body with attachment

​Error handling

​Common errors

​Related articles

​Prerequisites

​PHPMailer via Composer

​Install

​Basic send example

​HTML body with attachment

​Error handling

​Common errors

​Related articles

Prerequisites

PHPMailer via Composer

Install

Basic send example

HTML body with attachment

Error handling

Common errors

Related articles

Prerequisites

PHPMailer via Composer

Install

Basic send example

HTML body with attachment

Error handling

Common errors

Related articles