This question keeps coming up a lot on Stack Overflow for some reason: What was Stack Overflow built with? Some even wondered if Stack Overflow was built in Ruby on Rails. I consider that a compliment! This question has been covered in some detail in our podcasts, of course, but I know not everyone has time to listen to a bunch of audio footage to find the answer to their question. So, in that spirit, here's the technology "stack" of Stack Overflow, the stuff Jarrod, Geoff, and I used to build it: framework Microsoft ASP.NET language C# development environment Visual Studio web framework ASP.NET MVC browser framework jQuery database SQL Server 2008 data access layer LINQ to SQL source control Subversion (now Mercurial through Kiln) compare tool Beyond Compare source control integration VisualSVN (now, VisualHg) We have a few other minor dependencies as well, such as ReCaptcha, DotNetOpenId, and the WMD control (which we subsequently rewrote), but that's about it.