Twitter, WordPress, and Alibaba use PostCSS—and its most popular plugin, Autoprefixer; PostCSS has become one of the most popular CSS processors available. PostCSS plugins can do the same work as preprocessors (add vendor prefixes, use nested properties, variables, and mixins) with the advantage of enhanced modularity, performance, and power. Some plugins can extend CSS syntax and allow you to write CSS4 code right now, which is impossible on preprocessors.
PostCSS is very small, including only a CSS parser and AST stringifier, with all the CSS transformations encapsulated in modular plugins. Each plugin is a small JS function that receives a CSS node tree, applies transformations to it, and returns a modified tree. We’ll dive into why—and how—you can leverage PostCSS in your workflow today!