Send email with CSharp using SMTP Client and MailSlurp

Create a custom SMTP client and access MailSlurp inboxes from CSharp/DotNET.

You can use CSharp's built in SMTP client package System.Net.Mail. Let us use XUnit and the MailSlurp client to create an email address and send emails to it.

using System;
using System.Net;
using System.Net.Mail;
using mailslurp.Api;
using mailslurp.Client;
using mailslurp.Model;
using Xunit;

namespace SmtpService.Tests
    public class UnitTest1
        public void CanSendEmailWithMailSlurpSmtp()
            var apiKey = Environment.GetEnvironmentVariable("API_KEY")
                         ?? throw new ArgumentNullException("Missing API_KEY environment variable containing MailSlurp key");

            // configure client
            var config = new Configuration();
            config.ApiKey.Add("x-api-key", apiKey);
            var inboxController = new InboxControllerApi(config);

            // create an smtp inbox
            var inbox = inboxController.CreateInboxWithOptions(new CreateInboxDto(
                inboxType: CreateInboxDto.InboxTypeEnum.SMTPINBOX
            Assert.Contains("", inbox.EmailAddress);

            // get smtp host, port, password, username etc
            var imapSmtpAccessDetails = inboxController.GetImapSmtpAccess();
            var smtpClient = new SmtpClient(imapSmtpAccessDetails.SmtpServerHost)
                Port = imapSmtpAccessDetails.SmtpServerPort,
                Credentials = new NetworkCredential(userName: imapSmtpAccessDetails.SmtpUsername, password: imapSmtpAccessDetails.SmtpPassword),
                // disable ssl recommended
                EnableSsl = false
            // send email to inbox
            smtpClient.Send(from: "", recipients: inbox.EmailAddress, subject: "This inbound", body: "Hello");
            // wait for email to arrive
            var waitController = new WaitForControllerApi(config);
            waitController.WaitForLatestEmail(inboxId: inbox.Id, timeout: 30_000);

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