Enter a URL to check if the server has Gzip/Brotli compression enabled, showing compression ratio and bandwidth savings.
The Gzip Compression Test Tool helps developers and ops teams quickly check if a website has HTTP compression enabled, evaluate compression effectiveness, and optimize page load performance. Enabling Gzip/Brotli compression is a fundamental web performance optimization step.
HTTP compression reduces transfer size by compressing response bodies on the server. Gzip is the most widely supported algorithm, reducing text files by 60-80%. Brotli is a newer algorithm by Google with 15-25% better compression than Gzip, but requires HTTPS. Browsers declare supported compression via the Accept-Encoding request header, and servers indicate the compression used via the Content-Encoding response header.
Enter the URL in the input field and click the 'Test Compression' button. The tool checks the Content-Encoding header in the server response to determine if Gzip or Brotli compression is enabled, and calculates the bandwidth savings.
Gzip is the traditional HTTP compression method supported by virtually all browsers. Brotli is a newer algorithm developed by Google with 15-25% better compression ratios than Gzip, but requires HTTPS. Modern browsers support Brotli, which is recommended as the preferred option.
Gzip compression can reduce HTML, CSS, JavaScript and other text files by 60-80%, significantly reducing data transfer and speeding up page loads. Google uses page speed as a ranking factor, making compression a fundamental Core Web Vitals optimization step.
Nginx: Add gzip on; gzip_types text/css application/javascript to your config. Apache: Use the mod_deflate module. Node.js: Use the compression middleware. CDNs like Cloudflare typically enable compression by default.
No. JPEG, PNG, GIF, WebP and other image formats are already compressed. Applying Gzip compression to them won't reduce file size and may even increase it. Gzip compression is primarily useful for HTML, CSS, JavaScript, JSON, XML, and SVG text files.