PostCSS is a tool for transforming CSS with JavaScript. It can be used to develop a template language such as Sass and LESS. The PostCSS core consists of:

• CSS parser that generates an abstract syntax tree

• Set of classes that comprises the tree

• CSS generator that generates a CSS line for the object tree

• Code map generator for the CSS changes made#

There are official tools making it possible to use PostCSS with build systems such as Webpack, Gulp, and Grunt. There is also a console interface available. Browserify or Webpack can be used to open PostCSS in a browser.

The complete plugin list can be found on postcss.parts, with some examples listed below.

• Autoprefixer to add and clear browser prefixes.

• CSS Modules to get CSS selectors isolated and code organized. It is supplied as part of Webpack.

• stylelint to analyze CSS code for mistakes and check style consistency.

• stylefmt fixes the CSS code according to the stylelint settings.

• PreCSS to perform some Sass/Less preprocessing functions.

• postcss-preset-env to emulate features from unfinished CSS specification drafts.

• cssnano to make CSS smaller in size by getting rid of the spaces and rewriting the code.

• RTLCSS to change CSS code so that the design should be suitable for right-to-left writing (such is applied in Arabic and Hebrew).

• postcss-assets, postcss-inline-svg and postcss-sprites to work with graphics.