My musings about .NET and what not

A Better SMTP Development Server

Looking for a way to test the email sending functionality of your application? There’s no need to install a full-blown SMTP server – not as long as you have Antix SMTP Server for Developers in your bag of tricks.

I happened to catch my friend Chris Love’s latest blog post on testing email functionality. In this post, he talks about a tool called Neptune, developed by Donavan Brown at Notion Solutions.

Quite frankly, I hadn’t ever heard of Neptune, so I popped on over to check it out. It appears that a lot of folks have taken to this neat little utility. While I have no doubt Neptune gets the job done, there’s another SMTP development server I’ve been using for a few months that I think offers several advantages.

Like Neptune, Antix SMTP Server for Developers isn’t a “server” in the true sense of the word. It merely runs as a background process and emulates the functionality of a real SMTP server – without actually sending any emails, of course.

Antix can be deployed on any machine on your network. Once launched, it sits quietly in the notification area, waiting to snag any email sent from an SMTP client running on that network. When it does, it persists the email to a directory of your choosing, It also lists all of the emails in a little window. Double-click on any email in the list, and it opens for viewing in your email client! This lets you check formatting and content, as well as resend or forward the messages to other developers on your team.

As far as I’m concerned, the ability to persist and view the results are essential features (neither of which Neptune offers).

Another neat touch is that Antix uses ClickOnce deployment, so it automatically checks for the latest version each time you close the application.

And oh… did I mention that Antix SMTP Server for Developers is open source? Yep, you can download the source code right from CodePlex.

If you’re looking for a really great, totally free, open source SMTP emulator, you definitely owe it to yourself to give Antix SMTP Server for Developers a try.

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    » Comments

    1. John Sheehan avatar

      Alternately you can have emails delivered to a folder on your computer by modifying a value in your web.config:

      John Sheehan — June 25, 2009 10:48 AM
    2. bin avatar

      this trick with web.config not always work in every Windows environment.

      Thx for the article, this "smtp server" looks better than Naptune.


      bin — June 25, 2009 11:09 AM
    3. Lee Dumond avatar

      @John Sheehan That works as long as all you do on your dev box is ASP.NET. Keep in mind a lot of us are also doing PHP, MonoRail, etc. and this solution works for all of those scenarios too.

      Lee Dumond — June 25, 2009 11:27 AM
    4. mikedopp avatar

      Not sure I like this only because you have to install it. Try this instead: much easier to use.

      mikedopp — June 25, 2009 1:08 PM
    5. Nick Berardi avatar

      Hey Lee,

      Have you tried using the drop box method of using the specified pickup directory? It basically creates a folder on your harddrive and just drops the e-mails there, very useful for testing.

      Nick Berardi — July 1, 2009 9:36 AM
    6. Lee Dumond avatar

      @Nick - yes, that is the method that John Sheehan referenced in the first comment.

      That is more or less how Antix works behind the scenes, but it also provides convenient notification and a nice UI over that. Plus, it works if you're developing with other server technologies besides ASP.NET. And, it's free. ;)

      Lee Dumond — July 1, 2009 9:50 AM
    7. Susan avatar

      I recently came across your blog and have been reading along. I thought I would leave my first comment. I don't know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.


      Susan — July 31, 2009 5:35 AM
    8. twig avatar

      Exactly what I was looking for, thanks!

      twig — December 8, 2009 5:49 PM
    9. Rob avatar

      Also check out

      Rob — December 9, 2009 4:08 PM
    10. Derek Morrison avatar

      When you said " persists the email to a directory of your choosing...", did you mean that once it catches an email, you can manually move the .eml file using the File and Folder Tasks pane on the left side?

      When I first read your post, I thought you were saying that the app could be configured to automatically dump emails to a directory.

      Derek Morrison — January 28, 2010 3:00 AM
    11. Lee Dumond avatar

      Derek - good point. I'm sorry I didn't make that very clear. The app doesn't let you configure the directory directly, but the directory is accessible using the OS file system explorer.

      Of course, since there are emails, you can also forward, resend, or anything else you can do with email.

      Interesting idea -- since the tool is open source, I don't think it would be difficult to modify it to allow you to specify the directory.

      Lee Dumond — January 29, 2010 9:39 AM

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