The Very Best 4 (Active) CSS Lint Tools


Linting tools help improve the code quality and optimize it for better performance. Linting tools have sets of defined rules to verify the code, without actually executing the code. Web designers often overlook the CSS code quality and unstructured coding style. As the product grows, this can create a real mess and usually results in a lot of difficulty finding and fixing the issues. You will find many articles with lists of CSS linting tools, but unfortunately most of the tools are no longer available. Hence, this post talks about the 4 best ACTIVE CSS linting tools which you can leverage to validate and optimize your CSS code. Enjoy!

  1. CSSLint

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CSS Lint is an open source CSS code quality tool to find out problems with your CSS code. It was released in June 2011 at the Velocity conference. It does basic syntax checking as well as applying a set of rules to the code that look for problematic patterns or signs of inefficiency. The rules are all pluggable, so you can easily write your own or omit ones you don’t want. It is written in JavaScript which runs the whole CSS linting process.

CSS Lint can be easily integrated with your favorite IDE to make checking your CSS code quality easy. CSS Lint can be run on the command line so you can incorporate it into your build system.


  1. StyleLint

StyleLint is a mighty, modern CSS linter and fixer that helps you avoid errors and enforce consistent conventions in your stylesheets. It features:

  • Over one hundred and fifty rules to catch errors, limit language features and enforces stylistic conventions.
  • Support for the latest CSS syntax
  • Understands CSS-like syntaxes
  • Only enable the rules you want and configure them with options that tailor the linter to your needs.
  • Support for creating your own rules and add them to the linter.
  • Automatically fixes some stylistic warnings
  • Shareable configs
  • Over ten thousand tests cover the internals and rules.
  • Large growing community and used by major companies like Facebook, GitHub, Wikimedia, GSA, and WordPress among others.


  1. CSSNano

CSSNano is a modern, modular compression tool written on top of the PostCSS ecosystem, which allows us to use a lot of powerful features in order to compact CSS appropriately. It takes your nicely formatted CSS and runs it through many focused optimizations, to ensure that the final result is as small as possible for a production environment. By default, CSSNano performs safe optimizations on your CSS file, but we also offer an advanced preset with techniques that you can use to maximize compression.

CSSNano is powered by PostCSS, a tool for transforming styles with JavaScript. This allows you to insert CSSNano into your build step, along with other processors that can lint your CSS for errors, or transpile future syntax.



  1. Dirty Markup

Dirty Markup is a free web-based application for cleaning up such code very easily. It cleans, formats, and validates HTML (5), CSS and JavaScript by using the powers of the popular HTML Tidy, CSS Tidy and JS Beautify. The newest version also offers free public API which you can use to clean your code programmatically from your own app or plugin. It can be also a great option to validate your CSS on the fly. The provided editor is simple and provides real time error messages and notifications.



Optimized CSS code is a must for any website for best performance. The CSS linting tools help create clean, validated and optimized code based on predefined sets of rules. This post briefly talk about 4 of the best actively maintained CSS linting tools to help you write better CSS code.

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