A CSS minifier that performs structural optimizations to significantly reduce file size.
CSSO is a CSS minifier and optimizer that reduces CSS file size through structural transformations. It performs cleaning, compression, and restructuring of CSS code to eliminate redundancy and produce minimal output. Unlike basic minifiers, it analyzes and merges CSS rules for maximum efficiency.
Frontend developers and build engineers who need to optimize CSS for production websites and applications, especially those using modern build tools like webpack, Gulp, or PostCSS.
Developers choose CSSO for its advanced structural optimizations that often produce smaller CSS than other minifiers. Its integration with CSSTree provides reliable parsing, and its plugin ecosystem makes it easy to incorporate into existing workflows.
CSS minifier with structural optimizations
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Merges duplicate rules and declarations through restructuring, often producing smaller CSS than basic minifiers, as shown in the compression examples.
Leverages JSON usage data to aggressively remove unused CSS, enabling more targeted optimizations for reduced file size.
Offers plugins for webpack, Gulp, PostCSS, and more, making it easy to incorporate into existing development workflows.
Generates source maps that map minified CSS back to original source, facilitating debugging in production environments.
Advanced optimizations require providing and maintaining JSON usage data, adding configuration overhead and complexity.
The syntax API and AST format depend on CSSTree and may change, posing challenges for projects relying on direct AST manipulation.
Options like forceMediaMerge are marked as unsafe and could break CSS in edge cases, requiring careful validation.