GZIP Compression Test

Check if a website uses GZIP, Brotli, or Deflate compression and measure savings.

What This Tool Checks

Comprehensive analysis of HTTP compression for any website.

Compression Detection

Detects GZIP, Brotli, and Deflate compression from the Content-Encoding response header.

Size Comparison

Shows compressed vs. uncompressed size with a visual bar chart and savings percentage.

Response Time

Measures server response time to help you understand the full performance picture.

Transfer Details

Reports content-encoding, transfer-encoding, and content-length headers for debugging.

How It Works

Three steps to test your site's compression.

Enter a URL

Type or paste any URL. The tool will send requests with and without compression headers.

Measure Compression

The server response is analyzed for compression encoding, sizes are compared to calculate savings.

View Results

See whether compression is enabled, the type used, how much bandwidth is saved, and response time.

Frequently Asked Questions

Common questions about HTTP compression.

GZIP is a file compression algorithm used by web servers to reduce the size of HTML, CSS, JavaScript, and other text-based files before sending them to the browser. This reduces bandwidth usage and speeds up page load times. Most modern web servers and browsers support GZIP compression natively.

Brotli (br) is a newer compression algorithm developed by Google that typically achieves 15-25% better compression ratios than GZIP for text content. Brotli is supported by all modern browsers over HTTPS connections. Many servers now serve Brotli when supported, with GZIP as a fallback.

GZIP typically reduces text-based files by 60-80%. Brotli can achieve 70-85% reduction. The exact savings depend on the content type and size. HTML, CSS, JavaScript, JSON, and XML benefit most. Images and videos are already compressed and should not be GZIP-compressed.

In Apache, enable mod_deflate. In Nginx, add gzip on and configure gzip_types for text content types. Most hosting providers and CDNs like Cloudflare enable compression by default. Check your server documentation for specific configuration instructions.