Configure WordPress SMTP Email

Configure WordPress SMTP Email

Fix WordPress email delivery issues by configuring SMTP (Simple Mail Transfer Protocol) to send emails reliably through services like Gmail, SendGrid, or Mailgun.

// Configure SMTP settings for WordPress
function configure_smtp_settings($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.gmail.com'; // Your SMTP server
    $phpmailer->SMTPAuth   = true;
    $phpmailer->Port       = 587; // or 465 for SSL
    $phpmailer->Username   = 'your-email@gmail.com';
    $phpmailer->Password   = 'your-app-password'; // Use app-specific password
    $phpmailer->SMTPSecure = 'tls'; // 'tls' or 'ssl'
    $phpmailer->From       = 'your-email@gmail.com';
    $phpmailer->FromName   = 'Your Site Name';
}
add_action('phpmailer_init', 'configure_smtp_settings');

// Set default from email
function custom_wp_mail_from($original_email_address) {
    return 'your-email@yourdomain.com';
}
add_filter('wp_mail_from', 'custom_wp_mail_from');

// Set default from name
function custom_wp_mail_from_name($original_email_from) {
    return 'Your Website Name';
}
add_filter('wp_mail_from_name', 'custom_wp_mail_from_name');

Gmail Configuration

// Gmail SMTP configuration
function setup_gmail_smtp($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.gmail.com';
    $phpmailer->SMTPAuth   = true;
    $phpmailer->Port       = 587;
    $phpmailer->Username   = 'your-email@gmail.com';
    $phpmailer->Password   = 'your-16-digit-app-password';
    $phpmailer->SMTPSecure = 'tls';
    $phpmailer->From       = 'your-email@gmail.com';
    $phpmailer->FromName   = get_bloginfo('name');

    // Enable verbose debug output (disable in production)
    // $phpmailer->SMTPDebug = 2;
}
add_action('phpmailer_init', 'setup_gmail_smtp');

SendGrid Configuration

// SendGrid SMTP configuration
function setup_sendgrid_smtp($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.sendgrid.net';
    $phpmailer->SMTPAuth   = true;
    $phpmailer->Port       = 587;
    $phpmailer->Username   = 'apikey'; // This is always 'apikey'
    $phpmailer->Password   = 'your-sendgrid-api-key';
    $phpmailer->SMTPSecure = 'tls';
    $phpmailer->From       = 'noreply@yourdomain.com';
    $phpmailer->FromName   = get_bloginfo('name');
}
add_action('phpmailer_init', 'setup_sendgrid_smtp');

Mailgun Configuration

// Mailgun SMTP configuration
function setup_mailgun_smtp($phpmailer) {
    $phpmailer->isSMTP();
    $phpmailer->Host       = 'smtp.mailgun.org';
    $phpmailer->SMTPAuth   = true;
    $phpmailer->Port       = 587;
    $phpmailer->Username   = 'postmaster@your-domain.mailgun.org';
    $phpmailer->Password   = 'your-mailgun-password';
    $phpmailer->SMTPSecure = 'tls';
    $phpmailer->From       = 'noreply@yourdomain.com';
    $phpmailer->FromName   = get_bloginfo('name');
}
add_action('phpmailer_init', 'setup_mailgun_smtp');

Environment Variables (Secure Method)

// Use environment variables for credentials (recommended)
// Add to wp-config.php:
// define('SMTP_HOST', 'smtp.gmail.com');
// define('SMTP_PORT', 587);
// define('SMTP_USER', 'your-email@gmail.com');
// define('SMTP_PASS', 'your-password');
// define('SMTP_FROM', 'noreply@yourdomain.com');
// define('SMTP_NAME', 'Your Site Name');

function setup_smtp_from_env($phpmailer) {
    if (defined('SMTP_HOST')) {
        $phpmailer->isSMTP();
        $phpmailer->Host       = SMTP_HOST;
        $phpmailer->SMTPAuth   = true;
        $phpmailer->Port       = SMTP_PORT;
        $phpmailer->Username   = SMTP_USER;
        $phpmailer->Password   = SMTP_PASS;
        $phpmailer->SMTPSecure = 'tls';
        $phpmailer->From       = SMTP_FROM;
        $phpmailer->FromName   = SMTP_NAME;
    }
}
add_action('phpmailer_init', 'setup_smtp_from_env');

Test Email Function

// Test email sending
function send_test_email() {
    $to = 'test@example.com';
    $subject = 'WordPress SMTP Test Email';
    $message = 'This is a test email sent from WordPress using SMTP.';
    $headers = array(
        'Content-Type: text/html; charset=UTF-8',
        'From: Your Site <noreply@yourdomain.com>'
    );

    $sent = wp_mail($to, $subject, $message, $headers);

    if ($sent) {
        echo 'Test email sent successfully!';
    } else {
        echo 'Failed to send test email.';
    }
}

// Run this function once to test
// send_test_email();

Error Logging

// Log email errors
function log_email_errors($wp_error) {
    if (is_wp_error($wp_error)) {
        error_log('Email Error: ' . $wp_error->get_error_message());
    }
}
add_action('wp_mail_failed', 'log_email_errors');

// Enable SMTP debugging (only for troubleshooting)
function enable_smtp_debugging($phpmailer) {
    $phpmailer->SMTPDebug = 2; // Set to 0 in production
    $phpmailer->Debugoutput = function($str, $level) {
        error_log("SMTP Debug level $level: $str");
    };
}
// add_action('phpmailer_init', 'enable_smtp_debugging');

HTML Email Template

// Send HTML email with custom template
function send_custom_html_email($to, $subject, $message) {
    $headers = array(
        'Content-Type: text/html; charset=UTF-8',
        'From: ' . get_bloginfo('name') . ' <noreply@yourdomain.com>',
    );

    $html_message = '
    <!DOCTYPE html>
    <html>
    <head>
        <meta charset="UTF-8">
        <style>
            body { font-family: Arial, sans-serif; line-height: 1.6; }
            .container { max-width: 600px; margin: 0 auto; padding: 20px; }
            .header { background: #0073aa; color: white; padding: 20px; text-align: center; }
            .content { padding: 20px; background: #f9f9f9; }
            .footer { padding: 20px; text-align: center; font-size: 12px; color: #666; }
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>' . get_bloginfo('name') . '</h1>
            </div>
            <div class="content">
                ' . wpautop($message) . '
            </div>
            <div class="footer">
                <p>&copy; ' . date('Y') . ' ' . get_bloginfo('name') . '. All rights reserved.</p>
            </div>
        </div>
    </body>
    </html>
    ';

    return wp_mail($to, $subject, $html_message, $headers);
}

Features

• Reliable Delivery: Use professional SMTP services
• Multiple Providers: Supports Gmail, SendGrid, Mailgun, etc.
• Secure: Use environment variables for credentials
• Debugging: Built-in error logging
• HTML Support: Send formatted HTML emails
• Testing: Test function to verify configuration

Gmail App Password Setup

1. Enable 2-Factor Authentication on your Google account
2. Go to Google Account > Security > App Passwords
3. Generate an app-specific password
4. Use this 16-digit password in your SMTP configuration

Common SMTP Ports

• 587: TLS/STARTTLS (recommended)
• 465: SSL
• 25: Non-encrypted (not recommended)