How do I send an email using ASP.NET? Print

How to Send Email from ASP.NET Applications

SMTP Settings for Adaptive Web Hosting

ASP.NET Core / .NET 8/9/10 (Recommended)

Option 1: Using MailKit (Recommended)

First, install the NuGet package:

dotnet add package MailKit

Then send email:

using MailKit.Net.Smtp;
using MimeKit;

public async Task SendEmailAsync(string to, string subject, string body)
{
    var message = new MimeMessage();
    message.From.Add(new MailboxAddress("Your Name", "from@yourdomain.com"));
    message.To.Add(new MailboxAddress("", to));
    message.Subject = subject;
    message.Body = new TextPart("html") { Text = body };

    using var client = new SmtpClient();
    await client.ConnectAsync("mail.yourdomain.com", 587, MailKit.Security.SecureSocketOptions.StartTls);
    await client.AuthenticateAsync("from@yourdomain.com", "your-password");
    await client.SendAsync(message);
    await client.DisconnectAsync(true);
}

Option 2: Using System.Net.Mail (Built-in)

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

public async Task SendEmailAsync(string to, string subject, string body)
{
    using var message = new MailMessage();
    message.From = new MailAddress("from@yourdomain.com", "Your Name");
    message.To.Add(new MailAddress(to));
    message.Subject = subject;
    message.Body = body;
    message.IsBodyHtml = true;

    using var client = new SmtpClient("mail.yourdomain.com", 587)
    {
        Credentials = new NetworkCredential("from@yourdomain.com", "your-password"),
        EnableSsl = true
    };

    await client.SendMailAsync(message);
}

Configuration in appsettings.json

{
  "EmailSettings": {
    "SmtpServer": "mail.yourdomain.com",
    "Port": 587,
    "Username": "from@yourdomain.com",
    "Password": "your-password",
    "FromEmail": "from@yourdomain.com",
    "FromName": "Your Application"
  }
}

Email Service with Dependency Injection

// In Program.cs
builder.Services.Configure<EmailSettings>(
    builder.Configuration.GetSection("EmailSettings"));
builder.Services.AddTransient<IEmailService, EmailService>();

// EmailService.cs
public class EmailService : IEmailService
{
    private readonly EmailSettings _settings;

    public EmailService(IOptions<EmailSettings> settings)
    {
        _settings = settings.Value;
    }

    public async Task SendEmailAsync(string to, string subject, string body)
    {
        // Use MailKit or SmtpClient as shown above
    }
}

ASP.NET Framework 4.x (Legacy)

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

MailMessage message = new MailMessage();
message.From = new MailAddress("from@yourdomain.com");
message.To.Add(new MailAddress("to@example.com"));
message.Subject = "Test Email";
message.Body = "This is a test email.";
message.IsBodyHtml = true;

SmtpClient smtp = new SmtpClient();
smtp.Host = "mail.yourdomain.com";
smtp.Port = 587;
smtp.EnableSsl = true;
smtp.Credentials = new NetworkCredential("from@yourdomain.com", "your-password");

smtp.Send(message);

Web.config Configuration

<system.net>
  <mailSettings>
    <smtp from="from@yourdomain.com">
      <network host="mail.yourdomain.com"
               port="587"
               userName="from@yourdomain.com"
               password="your-password"
               enableSsl="true" />
    </smtp>
  </mailSettings>
</system.net>

Troubleshooting

Security Best Practices

• Never hardcode passwords in code - use configuration
• Always use TLS/SSL encryption (port 587 or 465)
• Use environment variables for production credentials
• Implement rate limiting to prevent abuse