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Compression Checker

Check whether your server compresses responses with gzip or Brotli.

Free, no signup. We fetch the page once and read what your server sends back.

Fetching the page…

What this checks

Text compression is close to free performance. Enabling it typically cuts HTML transfer size by 60 to 80 percent, and it is usually a single line of server configuration.

  • Content-Encoding header
  • Transfer size of the response

How to act on the result

  • If no compression is reported, enable gzip or Brotli. It is the cheapest speed win available.
  • Brotli compresses better than gzip and is supported by every current browser.
  • Compression applies to text: HTML, CSS, JS, SVG, JSON. Not to images.

Frequently asked

What is the difference between gzip and Brotli?

Both compress text. Brotli achieves roughly 15 to 20 percent smaller files but costs more CPU to compress. Most servers use Brotli where available and fall back to gzip.

How much does compression save?

For HTML, typically 60 to 80 percent of transfer size. On a slow mobile connection that is a visible difference.

How do I enable it?

On Apache, mod_deflate or mod_brotli. On Nginx, the gzip directive. On most managed hosting it is a toggle, and on many it is already on.

Should images be compressed this way?

No. JPEG, PNG and WebP are already compressed. Gzipping them wastes CPU for no gain.

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