---
title: Implementation Guide
---

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  Sass has a thriving community of implementations, with more being produced all
  the time. The core team loves to see new implementations thrive and mature,
  and they want to help out in any way they can.

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      ### Resources

      * [`sass-spec`](https://github.com/sass/sass-spec) is a suite of
        implementation-agnostic test cases for verifying that a Sass
        implementation behaves correctly. It's the best way to track your
        implementation's compatibility with the Sass reference implementation.

      * [How `@extend` Works](https://gist.github.com/nex3/7609394) is a
        fairly comprehensive run-down of the algorithm used by Sass's
        trickiest feature. Natalie still says that the implementation of
        `@extend` is the hardest code she's ever had to write, but luckily you
        don't have to figure it out from scratch.

      * **Reach out!** If you're working on a new implementation, we want to
        hear about it. Send an email to [Natalie](mailto:nex342@gmail.com) and
        [Chris](mailto:chris@eppsteins.net), tell us about the cool work
        you're doing, and ask about any corners of the language that don't
        quite make sense.

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      ### Requirements

      We whole-heartedly love new implementations of Sass, but we do have a
      few restrictions that we ask those implementations to follow in order to
      call themselves "Sass", "Sass implementations", or the like. Sass is a
      community as much as it is a language, and it's important that all
      implementations are willing to work for the good of the community.

      First, we ask that every implementation adopt the [Sass community
      guidelines](/community-guidelines) for their own implementation-specific
      communities. Much of what makes the Sass community strong is a culture
      of kindness and respect, and having clear and explicit guidelines helps
      produce that culture.

      Second, we ask that implementations not extend the language without
      agreement from the other major implementations and from the language
      designers, Natalie and Chris. The only reason a Sass community exists at
      all is because the language enables styles and frameworks to be shared
      among designers, and it's crucial for sharing that Sass code that works
      for one implementation works the same for all of them. In addition, it's
      important that there be a unified vision for the language design.

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    :markdown
      ### Making Language Changes

      Sass can still evolve as a language, of course. We're working on putting
      together a more explicit process for proposing and iterating on new
      language features, but for now all discussion of changes happens on [the
      Sass issue tracker](https://github.com/sass/sass/issues). Language
      changes are considered final when they're part of a stable release of
      the Ruby reference implementation.

      Language changes are discussed collaboratively, with particular weight
      given to the maintainers of mature Sass implementations. Attempts will
      be made to reach consensus with all stakeholders. However, this may be
      impossible in some circumstances, and the ultimate say lies with the
      lead designer of Sass, Natalie. Chris, the other core designer, also has
      veto power over any language change.