Is there some app/blog/site on the net that describes what technology is behind each Web Application? I would love to read about which wonderful technology that is powering the big WebApps like Reddit, Digg, Facebook, Stackexchange and so on.

Something similar to this for DuckDuckGo

  • 3
    I would have to ask as to whether this question actually belongs on here - it's not a specific question about a web application and it is just asking for a place where information is located - not a specific task which an app could perform.
    – nobody
    Jul 9, 2010 at 21:20
  • 1
    Thomas, I understand this and I did some thinking before posting it. It's actually both a request for a site and it's also interesting for power users of web applications so I think it belongs here.
    – grm
    Jul 10, 2010 at 9:08

7 Answers 7


High Scalability has a lot of very good articles on how the 'big' sites run and scale.


I use BuiltWith which has decent SEO type research as well


You can often tell about front-end technology. Sometimes it is obvious: if URL contains pages ending with .jsp, almost sure some J2EE server is involved (Tomcat, JBoss, Weblogic, ...). The ending ".asp" is usually old-style Microsoft ASP, .aspx is ASP.NET, .php is obviously PHP.

With ending like .do, .html it can be anything (quite often Java).

Often you can tell more by opening the source and reading on and/or looking into HTTP headers returned.

Where the things are really interesting is the middle ware and backend - is something like NoSQL database used or is it traditional relational database ? This is very hard to tell.

Best bet is either reading the Web site blog (if there is one) or trying to approach from other side: pick a technology (e.g. Cassandra) and read on their website in which projects is being used.

  • Note: In some cases legacy URLs like are kept (to not break links, or for SEO) even if the underlying technology has changed.
    – nic
    Jul 8, 2013 at 5:55

W3Techs is a plug-in for Firefox that tells you all about the technology used to run a website. Furthermore, you can also go directly to their website and enter the url to analyze.


If you use Google Chrome, try this extension:


If you are on Firefox, have a look for 'Backend Software Information' and 'W3Techs Website Technology Information' (as suggested previously), both of which are Firefox addons and support Firefox 3.6.

  • Thanks, but actually I would prefer builtwith.com as a bookmarklet. I'm looking for more insights in layers that goes deeper than this tool can find.
    – grm
    Jul 12, 2010 at 16:03
  • Fair enough :) If you like the builtwith apps then, it might be worth checking out the BuiltWith Chrome Extension if you use that. chrome.google.com/extensions/detail/… Jul 12, 2010 at 22:07

Wappalyzer is a Firefox extension that can detect several scripts, stats packages and javascript libraries.


You can't know the underlying technology for every webapp. All suggested tools/apps here are just general approaches to the matter.

For example, a lot of web developers are applying some filter methods to avoid sending headers telling the web browser what they are using in the back-end or even what web server is serving their webapp.

I'll give you a tip a friend gave me once: For a given website, if the general tools fail, go check their "Jobs" or "Careers" links and you'll know for sure what's in the black-box.

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