SMTP server written in C#. Doesn't actually deliver any mail, but perfect for testing that your app is correctly sending mail.
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Super-Smtp-Server is a tiny SMTP server that is designed to allow developers to quickly check the mail sending functions of their application are working.


  • Simple GUI
  • Multi-threaded, allows you to plug the server component into your own solution

What doesn't work

  • There's currently no kind of SMTP authentication available. You have to send mail without passwords and such.


  1. Start the server with: SuperSmtpGui.exe
  2. Point your mail-sending application to localhost, on port 25.
  3. Send your mail, get satisfaction from the fact that it shows in server's window.

That's it.

Slightly more complicated use

You can customise the port and ip address being used by the server. All configurations are contained in the App.config file.

Ip Address Binding

The line below defines the Ip Address being used by Super-Smtp-Sever.

  • Any means any ip address that your computer has.
  • If you want to specify an ip address, put it in standard IP for. (eg.

Port Binding

The line below defines the port that Super-Smtp-Server uses.

Screw your UI, I just want the server!

If you're unhappy with the GUI that comes with Supert-Smtp-Server, then I would suggest utilising the wonderfully simple server component of Super-Smtp-Server.

  1. Clone this git repo
  2. Include the 'SuperSmtpServer' project in your solution (add a reference to the project, duh)
  3. Add a using statement in your code using SuperSmtpServer;
  4. At an appropriate time, init the server component var server = new SmtpServer();
  5. Add an event handler to the MessageReceived event server.MessageRecieved += new MailMessageHandler(server_MessageRecieved);

Use the project in anyway you wish.