How to send an e-mail with PHP mailer and Microsoft OAuth 2.0

To send an email using PHP with Microsoft OAuth 2.0 authentication and PHP Mailer, you will need to:

1. Register your application with Microsoft and get the necessary credentials (client ID and client secret). You can do this by following the steps outlined in the Microsoft documentation: https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-register-app

2. Install the PHP OAuth 2.0 client library and PHP Mailer. You can use Composer to install these libraries:

composer require league/oauth2-client
composer require phpmailer/phpmailer
 

Use the OAuth 2.0 client library to get an access token. You can use the following code to get an access token:

use LeagueOAuth2ClientProviderMicrosoft;
$provider = new Microsoft([
    'clientId' => 'your-client-id',
    'clientSecret' => 'your-client-secret',
    'redirectUri' => 'http://your-redirect-uri/'
]);
// If the user has not authorized your app, redirect them to the Microsoft login page
if (!isset($_GET['code'])) {
    $authUrl = $provider->getAuthorizationUrl();
    header('Location: '.$authUrl);
    exit;
// If the user has authorized your app, get an access token
} else {
    $accessToken = $provider->getAccessToken('authorization_code', [
        'code' => $_GET['code']
    ]);
}
 

Use the access token and PHP Mailer to send an email. You can use the following code to send an email using PHP Mailer

use PHPMailerPHPMailerPHPMailer;
use PHPMailerPHPMailerSMTP;
$mail = new PHPMailer();
// Set the mailer to use SMTP
$mail->isSMTP();
// Set the SMTP server
$mail->Host = 'smtp.office365.com';
// Enable SMTP authentication
$mail->SMTPAuth = true;
// Set the SMTP authentication type (Microsoft OAuth 2.0)
$mail->AuthType = 'XOAUTH2';
// Set the OAuth 2.0 access token
$mail->oauthUserEmail = 'your-email@example.com';
$mail->oauthClientId = 'your-client-id';
$mail->oauthClientSecret = 'your-client-secret';
$mail->oauthRefreshToken = $accessToken;
// Set the email parameters
$mail->setFrom('your-email@example.com', 'Your Name');
$mail->addAddress('recipient@example.com', 'Recipient Name');
$mail->Subject = 'Email subject';
$mail->Body = 'Email body';
// Send the email
$mail->send();