Suggest an editImprove this articleRefine the answer for “What problems do postprocessors solve in modern frontend?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Postprocessors** close out the block of tasks related to the quality, compatibility and optimization of the final CSS, that is, everything that matters before a project reaches the user's browser. **Key point:** a preprocessor makes CSS convenient for the developer, while a postprocessor makes it convenient for the browser.Shown above the full answer for quick recall.Answer (EN)ImagePostprocessors close out the block of tasks related to the **quality, compatibility and optimization of the final CSS**, that is, everything that matters before a project reaches the user's browser. In modern frontend they are used in the following areas: --- ### **1. Cross-browser support** Postprocessors automatically add vendor prefixes and ensure styles work correctly across different browsers and versions. Example: `Autoprefixer`. --- ### **2. Optimizing CSS size** This includes: - minification (removing whitespace, line breaks, comments), - merging duplicate rules, - grouping media queries. The result: the CSS weighs less and loads faster. --- ### **3. Supporting new CSS capabilities** Postprocessors let you use experimental or future features of the standard, converting them into code that older browsers understand. Example: `postcss-preset-env`. --- ### **4. Removing unused styles** Extra rules that never occur in the HTML can be removed automatically: a task for tools like `PurgeCSS`. --- ### **5. Standardization and order inside CSS** Postprocessors can: - sort properties in a consistent style, - apply a code style, - turn "chaos" into a tidy structure, regardless of the development team. --- ### **6. Performance** Optimized CSS: less weight → faster loading → higher Lighthouse and Core Web Vitals scores, which affects UX and SEO. --- ### **Conclusion** Postprocessors solve tasks that are **not about writing CSS**, but about **bringing it up to production quality**: compatibility, minification, cleanliness, speed and support for future capabilities. A preprocessor makes CSS convenient for the developer, while a postprocessor makes it convenient for the browser.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.