Sass makes CSS much easier to work with and since many of the popular front-end frameworks are developing their CSS using SASS, it becomes essential to have friction-free support for it with ASP.NET MVC.

I just spent a few hours trying to figure out how to get ASP.NET MVC and Sass to work well together. There are so many packages on NuGet that claim to support sass, you would think it would be easy, but it was more challenging than I had expected.

Ultimately, I was able to get NSass to work the way I wanted it to and went with that, but here is what I found out along the way.

The ideal configuration

Before setting out to find a runtime solution, I currently was using the System.Web.Optimization packages and build / save time compilation of the sass files.

While this worked out reasonably well for me, it wasn't working for our designer who just wanted to edit the sass files and refresh the browser to see the changes. This meant that we needed a solution that would catch file modifications and then regenerate the css which was being minified by the System.Web.Optimization packages.


The SassAndCofee.AspNet package is by Paul Betts and it uses the SassAndCoffee.Ruby package. It seems to be primarily convention based and does minification, but doesn't integrate with the System.Web.Optimization classes.

While I did get this to work, it didn't work out for me because this library doesn't seem to support some newer functionality (specifically the interpolation stuff) so it threw an exception while parsing and then went into an infinite loop while trying to handle that exception. It likely will work once the ruby parser (embedded in the assembluy) is updated.

Unfortunately, this flaw basically makes many other packages not work.

Project Site -


The BundleTransformer.SassAndScss packages is very similar to SassAndCoffee.Ruby. It uses IronRuby and uses a ruby file to parse and compile the sass, but it can integrate with System.Web.Optimization to support bundling and minification. This package had the same problem as SassAndCoffee in that it ran into a parsing exception when it hit the interpolation operator, but it didn't go into a loop.

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The Bundler package is a member of the ServiceStack family. With this you create a .bundle file in your content directory which has the sass files you want in that bundle, then you run bundler.cmd (or is run automatically if you have a visual studio extension installed) and it will generate the css files and optionally minify them.

It also comes with some extensions in for MVC that give you functionality similar to those in System.Web.Optimization. Ultimately, I decided against using this because it wasn't that different than what I was already doing, but it does work and could be the ideal solution for many other people.

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I didn't evaluate the FubuMVC.Sass package since I am not using FubuMVC, but I will assume that it works.


There are a few packages to NSass:

  • NSass.Core is the core functionality to parse sass code and emit css
  • NSass.Optimization gives you a few classes that let you hook into System.Web.Optimization
  • NSass.Handler provides an IHttpHandler implementation that will parse requests to .scss files, which is what the System.Web.Optimization bundle will emit when in debug mode, so it's necessary when using it.

This project just wraps libsass and didn't run into the interpolation problem. This was simultaneously this simplest project to get running and the one that took the longest to get really running. It works absolutely fantastic out of the box, but you need to be sure that the machine you run it on has the Microsoft Visual C++ redistributable runtime installed. It took me forever to figure out that was the reason it wouldn't work on our web servers.

Once that problem is resolved, it is amazing.

Project Site -

Notable Mentions

Well, before trying to get all of this working, I was using MindScape's Web Workbench, but even that had problems which is why I began looking for a runtime solution rather than a build / save time solution. Once I had found NSass, all I needed next was the Visual Studio support back which is why I ended up creating SassyStudio.