postcss-normalize-url is a PostCSS plugin that normalizes URLs in your CSS, enhancing consistency and compatibility. It performs tasks like removing unnecessary quotes, simplifying protocol-relative URLs, and handling duplicate slashes. This leads to cleaner CSS, improved browser caching, and reduced file sizes. By standardizing URLs, the plugin helps prevent potential issues arising from inconsistent URL formats which could vary across different browsers or environments. Using postcss-normalize-url ensures more predictable behavior and a more maintainable codebase.