My Favorite Sass Tools

By Hugo Giraudel

Sass was introduced about 7 years ago as a workaround for CSS flaws and has come a long way since then. It has played a major role in popularizing CSS preprocessing, to the point where the question is no longer if you should use a preprocessor, but which one you should use. It turns out, the answer to that question is very often Sass — because the syntax is better (and closer to CSS), because it’s permissive, and because it can do a lot of stuff and works well.

Since being introduced, Sass has become arguably the most important CSS preprocessor available today. It has a whole ecosystem growing around it (starting with Compass) — Playgrounds, applications, grid systems, libraries, and so on… But it’s not always that easy to dig up interesting stuff about Sass. The more there is, the more you have to look in order to find the thing you want.

Hence this blog post. What if I tried to enlighten the path by showing you what I think are the most valuable Sass tools? Sounds cool right? Let’s go.


Getting started with Sass is not easy. Mostly because it is written in Ruby. And while Ruby is a popular language, front-end developers usually do not know Ruby. This is the main thing that leads beginners to use LESS or Stylus, which are written in JavaScript (Node, actually). People usually don’t want to add Ruby to their stack just to see what Sass is worth.

Fortunately, you can try Sass online. There are playgrounds, or online tools, that allow you to write Sass and see the compiled CSS and (sometimes) the way the code will render. As of writing this, there are two major playgrounds to play with Sass:


CodePen, by Chris Coyier, Alex Vasquez, and Tim Sabat, is by far the best playground you can use. It offers everything you need and beyond for front-end testing. Regarding Sass, it supports the stable version (version 3.3.4 as of writing) and you can use either the old indented syntax or the SCSS one.


You can also pick between Compass and Bourbon (or none). It also shows you syntax errors. It’s really awesome so if you don’t know about it yet, have a tour and give the Sass features a try.


SassMeister, by Jed Foster, is a playground that specializes only in Sass-related stuff. Obviously then, it does the job better than CodePen. You can use either stable, or Sass 3.2.14, or even LibSass, the C port of Sass (still running on Sass 3.1.x as of this writing).


Of course, SassMeister lets you choose the syntax you feel more comfortable with and you even can choose the output style (expanded, compressed, and so on). Most importantly, because SassMeister is specific to Sass, it allows you to import Sass libraries (Compass extensions actually). You can even propose your own extensions if you think they should be added.

To sum this up in a handy chart:

  CodePen SassMeister
Version Stable Stable or 3.2.14
LibSass No Yes
Output style Expanded Any
Allow extensions No Yes
Syntax Both Both
Custom editor Yes Kinda
Focused on Rendering Output

I think the last line kind of says it all: Because of its transversal nature, CodePen focuses on the rendering, i.e. what the page looks like once the DOM has been styled by your (somewhat preprocessed) CSS code and manipulated by your JavaScript. On the other hand, while SassMeister allows you to have a look at the rendering, I feel like it focuses more on the CSS output. CodePen makes it difficult to have a look at the compiled code because it’s the same editor for both the SCSS and the compiled CSS where you have to switch modes by clicking a button.

Note: there are also CSSDeck, JSBin, JSFiddle and some other playgrounds that offer preprocessor options, but they do not compare with CodePen and SassMeister when it comes to Sass.


Okay, code playgrounds are pretty cool when you want to experiment with Sass but when it comes to using Sass in an actual project, you’re on your own. You can’t defer the compilation to the playground or something. You have to do it by yourself — unless you decide to use a tool. There are quite a few apps for this but I feel two of them really stand out.


Prepros is a fairly new piece of software aimed at easing the pain of dealing with preprocessing compilation, especially when it comes to command line (ooooohh, the command line!).


It provides a neat user interface that lets you compile your sources seamlessly, without having to type a single command. I tried at launch and it was really cool so I think it’s a rock solid option.


CodeKit, on the other hand, is not brand new but has been freshened up upon moving to v2.0.


I’ve heard nothing but the best about CodeKit in the past so I can only assume CodeKit v2.0 is great. However I can see two downsides to CodeKit: First is the fact that it’s only available to Mac users, and it’s not free.

So to sum up:

  CodeKit Prepros
Cost $29 Free or $25 (pro)
Environment Mac Mac & Windows

If you don’t want to pay anything or are not using a Mac, go for Prepros. If you have a Mac and can spare the ~$25, then it depends. I’d say CodeKit has a better track record so far while Prepros is still fairly new.

Or you could just learn to use the command line…

Note: There are other options like, Scout (which I wouldn’t recommand due to some bugs and the fact that it no longer seems to be supported). But none of the alternatives compare with CodeKit and Prepros.

Grid Systems

There are hundreds of CSS grid systems to choose from. Many are built on top of a CSS preprocessor, most of which are using Sass. So when you have to pick an existing, solid, and powerful grid system based on Sass for a project, it can be complicated. How can you know which one is good and which one is not? Or which one deals with responsiveness nicely, and which one is easy enough to get started?

If you ask me, there are 2 grid systems written in Sass that really are above average., by Scott Kellum and Sam Richard, is not your average grid system. It provides a powerful API allowing you to create pretty much any kind of grid you want, controlling the number of columns, the gutter widths, aspect ratio, and lots more.


Singularity comes with a whole wiki to get you started.


Susy, by Eric M. Suzanne, just moved to version 2.0, making it a masterpiece of Sass code and helping you to deploy the wickedest grids.


Susy has to be one of the most interesting Sass projects I’ve ever seen and offers a complete documentation to learn how to use it.

  Singularity Susy
Default Isolation Float
Plugins Singularity Extras None
Requires Compass No No
Workflow integration Bower, Compass Compass, Bourbon, Bower, Yeoman

Both options are top-notch grid systems doing more than you’ll ever need to do, so feel free to pick one or the other. That being said, because Susy doesn’t depend on Compass, it makes it the perfect choice for projects running without Compass (e.g. projects powered by LibSass). Also, if you’re interested in reading Sass poetry, be sure to look at Susy’s source code!

Note: during early months of 2013, both grid systems were supposed to be merged into what would be called Susy Next. It is no longer the case and both projects still co-exist.

Testing Tools

Whether you are setting up a robust Sass architecture or writing a cool little library, there comes a time when you might want to test your code. While CSS is not something we are accustomed to testing, there are clever minds that have provided some smart tools to help test Sass code.

Matias Singers wrote a great article about this so I won’t go in-depth into the testing tools here, but let’s talk about three of them:


True, by Eric M. Suzanne, is a TDD-style framework for Sass, inspired by QUnit. It helps you in writing tests for your functions. I haven’t tried it myself but I’ve heard nothing but great things about it. For instance, it is the testing framework used for Susy, which we just discussed; also Compass plans on using True for its own tests.

Here is what a test would look like using True:

@include test-module('Column Math') {
    @include test('[function] is-symmetrical()') {
      @include assert-true(true, 'Number should be symmetrical');


Bootcamp, by James Kyle, is a BDD framework to test Sass functions, with a syntax really close to what Jasmine offers to JavaScript. What’s really cool about Bootcamp is that it exists as a Grunt plugin, making it the perfect choice to add in any project running on Grunt. I personally use it to test my Sass libraries (SassyLists, SassyCast, SassyJSON, SassyStrings, SassyMatrix) and I couldn’t be happier.

@include describe("A suite") {
  @include it("contains spec with an expectation") {
    @include should(expect(1 + 1), to(be(true)));

In summary:

  True Bootcamp
Based on Assert Expect
Inspired by QUnit Jasmine
Workflow integration Compass, Bower Grunt, Bower, npm
Weight Light Medium to heavy

As you can see, these two frameworks look similar. I like the fact that Bootcamp runs on Grunt and NPM with a very simple syntax. On the other hand, True has proven to work very well on Susy and is very lightweight. On a side note, Bootcamp 2 is in the pipeline and is going to make the syntax a whole simpler.


SCSS-Lint is, well, a lint tool for Sass. There are JSHint and JSLint for JavaScript, CSSLint for CSS, and now SCSS-Lint for Sass. SCSS-Lint helps you to keep a clean and tidy code base by raising warnings whenever there is something that doesn’t seem right. Like any linter, SCSS-lint allows you to specify your own rules with a configuration file, as shown below:

test.scss:2 [W] Prefer single quoted strings
test.scss:2 [W] Line should be indented 0 spaces, but was indented 1 space
test.scss:5 [W] Prefer single quoted strings
test.scss:6 [W] URLs should be enclosed in quotes


There are countless Sass libraries (most as Compass extensions). Since was created, it has never been easier to discover new extensions. Basically, is a plugin finder for Sass. You can look for a specific library, or tags, or simply browse through the best Sass extensions.

Among interesting/funny works, I’d like to mention:

Modernizr Helper Mixin

Modernizr Helper Mixin, by Daniel Guillan, is a very lightweight Compass extension that provides an extra simple API for Modernizr integration. Basically, it makes obvious what you are trying to do when you use Modernizr’s .no-* classes in your stylesheets.

/* SCSS */
.my-selector {
  @include yep(translate3d opacity) {
    transform: translate3d(0,100px,0);
    opacity: 0;
  @include nope(translate3d opacity) {
    top: 100px;
    display: none;

/* CSS */
.translate3d.opacity .my-selector {
  transform: translate3d(0,100px,0);
  opacity: 0;

.no-js my-selector,
.no-translate3d .selector,
.no-opacity .selector {
  top: 100px;
  display: none;

Quotation Marks

Quotation Marks, by Nico Hagenburger, is kind of a weird one — I like it very much. This micro-library helps you use accurate quotation marks depending on the language you’re using. It currently supports over 55 different languages and is easily extensible for more.

/* SCSS */
.my-class {
  @include quotation-marks(en);

/* CSS */
.my-class:before {
  content: "“";

.my-class:after {
  content: "”";


Animate.sass, by Polikin, is the honorable successor of Animate.css, a collection of plug-and-play CSS animations to enhance your interfaces. It doesn’t do much more than rewrite the original library by taking advantage of Sass features like loops, mixins, variables and such.

@include animation-keyframes(fading-entrances/fadeInRight);
.my-class {
  @include animations(fadeInRight);


HiDPI is a very valuable Compass extension written by Kaelig from The Guardian, seamlessly serving high-resolution background images to high-density (Retina) displays. Given how hard it is to deal with Retina displays, such a tool is a blessing.

/* SCSS */
.logo {
  @include hidpi(my-logo);

/* CSS */
.logo {
  background-image: url('../images/my-logo.png');
@media (-webkit-min-device-pixel-ratio: 1.3),
       (min-resolution: 124.8dpi),
       (min-resolution: 1.3dppx) {
  #logo-auto {
    background-image: url('../images/my-logo_x2.png');
    background-size: 250px 188px;


SassyJSON started as a fun project between Fabrice Weinberg and I, until we ended up with a JSON parser written in Sass. Basically, SassyJSON provides a simple API to encode and decode Sass within Sass.

@include json-encode(((a: (1 2 ( b : 1 )), b: ( #444444, false, ( a: 1, b: test ) ), c: (2 3 4 string))));
// {"a": [1, 2, {"b": 1}], "b": ["#444444", false, {"a": 1, "b": "test"}], "c": [2, 3, 4, "string"]}

$json-decode: json-decode('{"a": [1, 2, {"b": 1}], "b": ["#444444", false, {"a": 1, "b": "test"}], "c": [2, 3, 4, "string"]}');
// ("a": 1 2 ("b": 1), "b": #444444 false ("a": 1, "b": "test"), "c": 2 3 4 "string")

What is cool about SassyJSON is that it preserves Sass data types when decoding JSON. This means if you have a JSON string containing "#444444", it will be returned as a color in Sass. Same with a number, a length, an angle, or whatever. So you can definitely get JSON data, decode the data in Sass, and use them seamlessly in your stylesheet.

To help people use SassyJSON in real projects, for instance to synchronize configuration between Sass and JavaScript for shared modules, we added a JSON file importer in Ruby (that’s the only piece of Ruby in the entire project). With this you can import and decode a .json file to get access to its content in your stylesheet.

Final Thoughts

That’s pretty much it, folks! I think this is a decent round-up of Sass tools.

If you have any more interesting Sass tools and resources to share, be sure to drop a comment!

  • Adam

    The need of Compass for grid system is a major turn off for me. I’ve been waiting for Susy 2.0 (which already remove the dependency to Compass), but looks like to complex for me. Hugo, have you take a look at jeet grid system ( What’s your opinion about it?

    • I have seen it but not tested it; it looks clean and simple enough so I think it’s a decent choice. Perhaps it’s a bit recent to have feedbacks.

      That being said, I don’t see it or any grid being better than Susy 2 any time soon. This one is simply huge.

    • Scott Kellum

      Note that Singularity also removed its Compass dependency in 1.2.0. Jeet looks very good as well.

  • Danyel Perales

    Thanks a lot for sharing, never heard of some of them before.

    If you dont mind, can you explain the bug part about scout app please ? Thanks again

  • LouisLazaris

    Yep, someone pointed that out to Hugo on Twitter, and I’ve now corrected it. Thanks.

  • I don’t remember well, it was some time ago. Basically, without changing a single line of code, ScoutApp compilation was failing while manual command-line compilation was working fine.

    • danielarts

      Many thanks for Your interesting posting Hugo!
      I am now working with ScoutApp on Mac OS X since 2 moths and the app works like a breeze!

  • Dave Orb Schneider Toast

    Hey Hugo, Can you recommend any decent spriting alternatives to compass. Compass sprites are adding about 6 seconds to my compile time, which adds up over the day! Using latest version of Sass and Compass.

  • I have heard nothing but the best about Grumpicon: Anyway, there are a lot of Grunt (even Gulp I suppose) packages for this. :)

  • James Sterling

    No mention of Thoughtbot’s Neat grid framework?

  • Oliver

    I don’t understand why is not more popular. You can do a lot more with it than with Codekit. May be because it’s a bit more expensive ??

  • I haven’t included because it isn’t a Sass tool in itself. It’s an environment framework.

  • Could have. I just don’t know it well enough.

  • Christian

    I just started using Susy with breakpoint! Do you have any suggestions on how to handle rules you need to apply at multiple breakpoints/layouts?

    • I might be wrong but I think Breakpoint suits better a workflow since it’s from the same author.

      • Christian

        Breakpoint actually started as Susy functonality, but when another developer expanded upon it Susy took it out of it’s core and just suggested it’s use. They have a susy-breakpoint function in the toolkit for integration.

  • I’m trying to use animate-sass with build system gulp but It doesn’t work would you like to help me, whether I’ve to import compass?

  • Just got into streamlining my web process and been delving into Sass. Thanks for clarifying all the different aspects Sass can cover.

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