Outlook 365 SMTP Settings (2026)

// Using PHPMailer: composer require phpmailer/phpmailer
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

require 'vendor/autoload.php';

$mail = new PHPMailer(true);

try {
    // Microsoft 365 SMTP settings
    // For personal: use smtp-mail.outlook.com
    $mail->isSMTP();
    $mail->Host       = 'smtp.office365.com';
    $mail->SMTPAuth   = true;
    $mail->Username   = getenv('OUTLOOK_EMAIL');
    $mail->Password   = getenv('OUTLOOK_APP_PASSWORD');
    $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
    $mail->Port       = 587;

    // Important: From must match authenticated user
    $mail->setFrom(getenv('OUTLOOK_EMAIL'), 'Your Name');
    $mail->addAddress('recipient@example.com');

    $mail->isHTML(true);
    $mail->Subject = 'Hello from Outlook';
    $mail->Body    = '<h1>Welcome!</h1><p>This is a test email.</p>';
    $mail->AltBody = 'Welcome! This is a test email.';

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

// npm install nodemailer dotenv
const nodemailer = require('nodemailer');
require('dotenv').config();

// Microsoft 365 SMTP Configuration
// For personal: use smtp-mail.outlook.com
const transporter = nodemailer.createTransport({
    host: 'smtp.office365.com',
    port: 587,
    secure: false, // true for 465, false for 587
    auth: {
        user: process.env.OUTLOOK_EMAIL,
        pass: process.env.OUTLOOK_APP_PASSWORD
    },
    tls: {
        ciphers: 'SSLv3',
        rejectUnauthorized: false
    }
});

async function sendEmail() {
    try {
        const info = await transporter.sendMail({
            // Important: From must match authenticated user
            from: process.env.OUTLOOK_EMAIL,
            to: 'recipient@example.com',
            subject: 'Hello from Outlook',
            html: '<h1>Welcome!</h1><p>This is a test email.</p>'
        });

        console.log('Message sent: %s', info.messageId);
    } catch (error) {
        console.error('Error:', error);
    }
}

sendEmail();

using System.Net;
using System.Net.Mail;

// Microsoft 365 SMTP Configuration
var smtpClient = new SmtpClient("smtp.office365.com")
{
    Port = 587,
    Credentials = new NetworkCredential(
        Environment.GetEnvironmentVariable("OUTLOOK_EMAIL"),
        Environment.GetEnvironmentVariable("OUTLOOK_APP_PASSWORD")
    ),
    EnableSsl = true,
};

var mailMessage = new MailMessage
{
    // Important: From must match authenticated user
    From = new MailAddress(Environment.GetEnvironmentVariable("OUTLOOK_EMAIL")),
    Subject = "Hello from Outlook",
    Body = "<h1>Welcome!</h1><p>This is a test email.</p>",
    IsBodyHtml = true,
};

mailMessage.To.Add("recipient@example.com");

try
{
    smtpClient.Send(mailMessage);
    Console.WriteLine("Email sent successfully!");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}