Online CSS compression tool - Efficiently optimize CSS code, reduce size and increase speed

This free online CSS compression tool, based on the open-source clean-css engine, intelligently removes whitespace, line breaks, and comments, and supports custom compression levels. It significantly reduces CSS file size, bandwidth, and HTTP response size, thereby improving website loading speed and front-end performance. It's ideal for front-end performance optimization and reducing CSS file size.

Creative Inspiration

This tool is designed to address real-world issues such as slow first page rendering, limited mobile loading, and reduced SEO performance caused by bloated CSS. Its goal is to use industry-recognized compression algorithms to minimize transfer size without compromising stylesheet semantics, helping developers and site operators achieve measurable performance improvements.

How to Use

1. Paste the CSS code into the input area above.

2. Click the "Compress Code" button.

3. Copy the compressed code and replace it in your website files. Test and confirm it's correct before going live.

Application Scenarios

• Pre-launch static resource optimization (reducing CSS file size and improving FCP/LCP).

• Page acceleration for mobile devices and low-bandwidth environments.

• Performance optimization and SEO enhancement for e-commerce and content site homepages.

Implementation Principle

Based on the clean-css open-source engine, this optimization process is optimized to preserve lexical parsing and semantics: removing redundant whitespace, line breaks, and comments, merging duplicate rules, consolidating selectors and attribute representations, and rewriting as needed to reduce redundancy.

FQA

1. Will compression change the style?

   Generally not. Please verify in a test environment before use.

2. Does it support modern CSS (variables/media queries/Flexbox/Grid)?

   Common modern syntax and media queries are supported, and valid rules are not removed during the minification process.

3. How much speed can be improved after minification?

   Depending on the original CSS structure and the amount of redundancy, a size reduction of 20%–70% is generally possible; improvements are most noticeable on the initial page load and mobile experience.