Check GZIP compression
Check gzip compression of your website. Find if your website is served through gzip compression or not.
Free Gzip & Brotli Compression Checker
Test whether HTTP Gzip or Brotli compression is enabled on your server and calculate total bandwidth savings.
Quick Answer & Overview
The Gzip compression checker tests whether a web server returns compressed HTTP payloads (Gzip or Brotli) when responding to browser requests. It calculates uncompressed vs. compressed byte sizes, verifying that your site saves 70%+ bandwidth and passes Google Core Web Vitals speed audits.
Enter Webpage URL
Enter your target domain or URL (e.g., https://example.com) into the diagnostic scanner.
Send HTTP Accept-Encoding Header
Our scanner sends client request headers negotiating `Accept-Encoding: gzip, deflate, br`.
Inspect Response Headers
We analyze server response headers (`Content-Encoding`) and measure raw uncompressed vs compressed payload bytes.
Review Bandwidth Savings
Review compression status, percentage size reduction, and actionable server configuration guidance (Nginx, Apache, Cloudflare).
Accelerate Core Web Vitals & Slash Hosting Bandwidth
Delivering uncompressed HTML and JavaScript files forces mobile visitors to download massive payloads over cellular networks, leading to slow Largest Contentful Paint (LCP) times and higher bounce rates. Verifying active Gzip or Brotli compression ensures your server streams data in the most compact format possible.
70%+ Byte Savings
Compresses heavy JavaScript application bundles and CSS frameworks from 500KB down to 100KB.
Brotli (br) Detection
Detects modern next-gen Brotli compression algorithms for superior web performance.
Core Web Vitals Pass
Fixes the common Google PageSpeed Insights warning: "Enable text compression".
Comparing Uncompressed vs. Gzip vs. Brotli Compression
| Encoding Type | Sample 500KB JS Bundle | Bandwidth Reduction |
|---|---|---|
| None (Plaintext) | 500 KB | 0% (Slowest mobile transfer). |
| Gzip (gzip) | ~120 KB | ~76% Bandwidth saved. |
| Brotli (br) | ~95 KB | ~81% Bandwidth saved (Optimal). |
Frequently Asked Questions
What is Gzip compression and why is it important?
Gzip is a server-side compression algorithm that shrinks HTML, CSS, JavaScript, and JSON files before transmitting them over the internet. It typically reduces file sizes by 60% to 80%, drastically improving website load times.
What is the difference between Gzip and Brotli (br)?
Brotli is a newer compression algorithm developed by Google that yields 15% to 25% better compression ratios than Gzip, particularly on HTML and JavaScript text files.
Does Gzip compression improve Google SEO rankings?
Yes. Server compression directly accelerates page speed and Core Web Vitals (Largest Contentful Paint - LCP), which are confirmed Google ranking factors.
How do I enable Gzip compression on Nginx or Apache?
On Nginx, set `gzip on;` in nginx.conf. On Apache, enable `mod_deflate`. If you use a CDN like Cloudflare or Fastly, compression is typically enabled automatically.
Can image files (like JPG or PNG) be compressed with Gzip?
No. Images are already compressed raster formats. Enabling Gzip on images wastes server CPU and can actually increase file sizes. Gzip should only be applied to text-based assets (HTML, CSS, JS, SVG, JSON).
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