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Which tools and technologies build the Stack Exchange Network?

I know this is kind of off-topic, but just curious.

  • 2
    why isn't this a community wiki question? Nov 7, 2008 at 23:49
  • 6
    That's like 255 reputation for a single question! I think more rubyists should use stackoverflow. And maybe then, people will understand this question.
    – Jaryl
    Dec 28, 2008 at 19:01
  • 2
    For a more up-to-date answer to what Stack Overflow was built with see stackoverflow.com/questions/749358/…
    – Sam Hasler
    Apr 28, 2009 at 17:08
  • @nicael no, that's not the proper thing to do. If you really want the new close as duplicate banner to kick in, the question should be reopened and closed again as duplicate, feel free to flag as "Other" asking to do this, but chances it will be done are not high. Jun 9, 2014 at 9:34

8 Answers 8


In case you don't know, the question asker is a notable figure in the Ruby community, so this question is quite a compliment! :)

As others have noted, we use ASP.NET and the MVC framework. We're not platform advocates, necessarily; that's what we know. We take a lot of inspiration from other sites built in Ruby and other technologies, of course.

Oh, and thanks for stopping by, Obie!

Edit: I created a blog entry to answer this


Simple to find out via curl -I:

curl -I stackoverflow.com

The most important parts to answer your question are:

Server: Microsoft-IIS/7.0
X-AspNet-Version: 2.0.50727
X-Powered-By: ASP.NET
  • 6
    A Simple firebug->net would be enough
    – Itay Moav
    Mar 5, 2009 at 0:53
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    Hmmm ... curl -I to www.37signals.com and basecamphq.com is showing PHP/5.2.4 and PHP/5.2.6. but those products are not built with PHP, they are built with Rails.
    – Mike Berrow
    Mar 7, 2009 at 5:24
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    The server is apparently using php for something, and unless they are using passenger it won't show a X-Powered-By. They are most likely proxying to mongrel from apache for their rails apps.
    – gregf
    Apr 22, 2009 at 14:53
  • 1
    Sorry but I got this when i do curl -I stackoverflow.com HTTP/1.0 200 OK Cache-Control: public, max-age=32 Content-Length: 196001 Content-Type: text/html; charset=utf-8 Expires: Mon, 11 Jul 2011 04:23:33 GMT Last-Modified: Mon, 11 Jul 2011 04:22:33 GMT Vary: * Date: Mon, 11 Jul 2011 04:23:01 GMT X-Cache: MISS from atmosphere.sprout.lan X-Cache-Lookup: MISS from atmosphere.sprout.lan:3128 Via: 1.1 atmosphere.sprout.lan:3128 (squid/2.7.STABLE9) Connection: close Jul 11, 2011 at 4:25
  • Better yet , use this plugin - Wappalyzer . Tells you what all tools have been used in making the site . Gives the correct output 99% of the time :) Oct 20, 2014 at 7:21
  • at early time it was showing ASP.NET that was correct .. I read in wiki stackoverflow is written in c# but now when I open my PC Wappalyzer showing its's in PHP ¯_(ツ)_/¯
    – Kishan Oza
    Mar 25, 2019 at 5:02

ASP.NET MVC, listen to the podcasts at https://blog.stackoverflow.com/ for more information.

Check out this relevant PDC 2008 presentation by Phil Haack.


No, it's actually written in ASP.NET's MVC framework.


It's written in ASP.NET MVC, which bears some similarities to RoR as I understand it.


No, it is written on the .Net Platform. I know it uses ASP.Net MVC. If you want to get more information on the architecture and how it was built, check out some of the podcasts at https://blog.stackoverflow.com


Actually the best way to know what technology a web site is using is to install Server spy plugin in firefox which will tell you the web server used in a web page. so if it says IIS then it is using ASP. If Mongrel then rails. Apache can't tell you much you will need to do more research by looking at the extension in the uri, and also looking to the page source can give more details.

Mostly Rails web site, they will have prototype or script.aculo.us libraries in the html source.

  • 1
    IIS can also run PHP code via ISAPI, albeit that this configuration is probably not common
    – Otherside
    Oct 1, 2008 at 9:45
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    IIS can also act as a proxy to Mongrel, so at best it gives you the technology that is most likely to be powering it. Also it won't tell you which version of ASP
    – bjeanes
    Jan 23, 2009 at 22:06