Send ASP.NET mail through SecureSMTP

Setup

Send from your server with SMTP or one HTTPS request. There is no SDK to install.

1. 1

   Create a SecureSMTP account

   Sign up at securessmtp.com/signup. The Free plan includes 5,000 emails a month. No card needed.

2. 2

   Add a site and copy its API key

   Dashboard → Sites → + Add website. The last step shows the site’s API key (it starts with qcs_live_). It is shown only once, so copy it. The API keys page (/app/forms/api-keys) also shows the SMTP settings. Store the key in an environment variable (for example SECURESMTP_API_KEY). Never commit it or send it to the browser.

3. 3

   What to install

   Nothing to install — use System.Net.Mail.SmtpClient pointed at smtp.securessmtp.com, or HttpClient for the API.

4. 4

   Make your first send

   Copy the snippet below into a server-side endpoint or background job. Replace to, subject and the body with your own values.

5. 5

   Test it

   Trigger your endpoint once. With the API, check that the response has ok: true. The email shows up in the Email log in your dashboard.

// Program.cs
using System.Net.Mail;
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapPost("/api/contact", async (Contact data) => {
    using var smtp = new SmtpClient("smtp.securessmtp.com", 587);
    smtp.Credentials = new System.Net.NetworkCredential(
        "securessmtp",
        Environment.GetEnvironmentVariable("SECURESMTP_API_KEY"));
    smtp.EnableSsl = true;
    var msg = new MailMessage("[email protected]", "[email protected]",
                              "Contact", data.Message);
    await smtp.SendMailAsync(msg);
    return Results.Ok();
});

record Contact(string Message);

FAQ