How to Configure SMTP in WordPress (With and Without Plugin)

Method 1: Configuring SMTP via wp-config.php

This approach is simpler but less secure. In this method, we add our SMTP details directly to the wp-config.php file.

• Open the wp-config.php file: Find it in the root directory of your WordPress installation.
• Add the following code just above the line /* That’s all, stop editing! Happy blogging. */.
• Replace the PHP constant values with your SMTP provider’s information (e.g., Gmail, SendGrid, Mailgun).

Here’s an example setup using Gmail’s SMTP server:

// WordPress free Gmail SMTP server configuration
define( 'SMTP_HOST', 'smtp.gmail.com' );          // SMTP server for Gmail
define( 'SMTP_PORT', '587' );                     // SMTP port number
define( 'SMTP_USERNAME', 'youremail@gmail.com' ); // Your email address
define( 'SMTP_PASSWORD', 'your-app-password' );   // App password for Gmail
// It is recommended to use a business email address for the "From" email field,
// e.g., admin@diversifyindia.in. However, Gmail SMTP does not support custom email addresses in the free plan.
define( 'SMTP_FROM', 'youremail@gmail.com' );     // 'From' email address
define( 'SMTP_NAME', 'Your Name or Business' );   // 'From' name
define( 'SMTP_SECURE', 'tls' );                   // Encryption: 'ssl' or 'tls'
define( 'SMTP_AUTH', true );                      // Enables SMTP authentication

Note: If you’re using Gmail SMTP server, you may need to create an app password. You can generate this by visiting https://myaccount.google.com/apppasswords.

Method 2: Creating a Custom Settings Page

If you’re comfortable coding, you can create a custom settings page in WordPress to gather SMTP configuration details from users. This approach requires additional coding and a more complex setup, but it allows users to input their SMTP information directly in the WordPress dashboard.

For more information, please refer to our article on creating a settings page for SMTP plugins.

Setting Up the phpmailer_init WordPress Hook

WordPress’s wp_mail function uses the phpmailer_init hook to set up SMTP before sending emails. This function will configure SMTP each time wp_mail is used to send an email.

Here’s an example using Gmail’s SMTP settings:

// Configure SMTP with phpmailer_init
// This function receives a PHPMailer instance as an argument.
function setup_wp_smtp( $phpmailer ) {
    $phpmailer->isSMTP();                         // Send mail using SMTP
    $phpmailer->Host = 'smtp.gmail.com';          // Gmail SMTP server
    $phpmailer->Port = 587;                       // Use 587 for TLS
    $phpmailer->SMTPAuth = true;                  // Enable SMTP authentication
    $phpmailer->Username = 'youremail@gmail.com'; // Your Gmail email
    $phpmailer->Password = 'your-app-password';   // Your Gmail app password
    $phpmailer->SMTPSecure = 'tls';               // Secure connection
    $phpmailer->From = 'youremail@gmail.com';     // From email address
    $phpmailer->FromName = 'Your Name';           // From name
}
add_action( 'phpmailer_init', 'setup_wp_smtp' );

If you are storing your SMTP details in the wp-config.php file, you can modify the setup_wp_smtp function to use those constants instead, as shown below:

function setup_wp_smtp( $phpmailer ) {
    $phpmailer->isSMTP();
    $phpmailer->Host = SMTP_HOST;
    $phpmailer->Port = SMTP_PORT;
    $phpmailer->SMTPAuth = SMTP_AUTH;
    $phpmailer->Username = SMTP_USERNAME;
    $phpmailer->Password = SMTP_PASSWORD;
    $phpmailer->SMTPSecure = SMTP_SECURE;
    $phpmailer->From = SMTP_FROM;
    $phpmailer->FromName = SMTP_NAME;
}
add_action( 'phpmailer_init', 'setup_wp_smtp' );

If you are gathering SMTP configuration information through a settings page and storing it in the WordPress database using the update_option function, you can use the get_option function to retrieve those settings. Here’s an example:

function setup_wp_smtp( $phpmailer ) {
    $smtp_config = get_option( "smtp_config" );
    $phpmailer->isSMTP();
    $phpmailer->Host = $smtp_config['host'];
    $phpmailer->Port = $smtp_config['port'];
    $phpmailer->SMTPAuth = $smtp_config['auth'];
    $phpmailer->Username = $smtp_config['username'];
    $phpmailer->Password = $smtp_config['password'];
    $phpmailer->SMTPSecure = $smtp_config['security_type'];
    $phpmailer->From = $smtp_config['from_email'];
    $phpmailer->FromName = $smtp_config['from_name'];
}
add_action( 'phpmailer_init', 'setup_wp_smtp' );

For more information on sending emails in WordPress, refer to our article on how to send emails using the wp_mail function.