Check Gzip Compression
Verify if your website serves compressed responses. Supports Gzip, Brotli, Deflate and Zstandard compression detection.
Free Gzip Compression Checker — Verify Server Compression
Gzip and Brotli compression are among the most impactful and easiest performance improvements you can make to a website. Enabling compression on your web server reduces the size of HTML, CSS, JavaScript, and XML files by 60–80% before they are sent to visitors. Smaller files transfer faster, reducing page load time and improving Core Web Vitals scores.
This free Gzip Compression Checker tests any URL and reports whether the server is using compression, which algorithm is active (Gzip, Brotli, or Deflate), the original file size, the compressed size, and the compression ratio. If compression is not enabled, you are leaving significant performance gains on the table.
Most major web servers — Apache, Nginx, and Cloudflare — support Gzip and Brotli out of the box. In many cases, enabling compression requires only a few lines of server configuration.
Gzip vs Brotli — Which Is Better?
Gzip has been the standard web compression algorithm since the early 2000s. It is supported by virtually every browser and server. Brotli, developed by Google and released in 2015, typically achieves 15–25% better compression ratios than Gzip for text files. Modern browsers all support Brotli over HTTPS.
For best performance, configure your server to offer Brotli first and fall back to Gzip for older clients. Cloudflare, AWS CloudFront, and most modern CDNs support Brotli natively.
Deflate is an older algorithm rarely used today. If your server is using Deflate, consider upgrading to Gzip or Brotli.
How to Enable Gzip Compression
Apache. Add AddOutputFilterByType DEFLATE text/html text/css application/javascript to your .htaccess or server config.
Nginx. Add gzip on; and gzip_types text/html text/css application/javascript; to your nginx.conf.
Cloudflare. Gzip and Brotli are enabled automatically for all Cloudflare-proxied traffic. No configuration required.
Node.js / Express. Use the compression middleware package to enable Gzip for all responses.
Why Compression Matters for SEO
Faster page loads. Smaller files transfer in less time, directly improving LCP and overall PageSpeed score.
Reduced bandwidth costs. Compression reduces the amount of data transferred, lowering hosting bandwidth consumption.
Better crawl efficiency. Googlebot downloads compressed pages faster, allowing it to crawl more pages within the crawl budget.
Related Tools
- Page Speed Checker – Test full page performance.
- HTTP Headers Checker – View all server response headers.
- Page Size Checker – Check total page download size.
Frequently Asked Questions
What is Gzip compression?
A compression algorithm that reduces HTML, CSS, and JavaScript file sizes before sending them to browsers.
Does it help SEO?
Yes. Smaller files load faster, improving PageSpeed scores and Core Web Vitals.
What is Brotli?
A newer compression algorithm by Google that compresses 15–25% better than Gzip.
Is this tool free?
Yes. Completely free, no sign-up needed.