Paste your HTML, CSS or JS and get real measured GZIP byte savings. URL checks report only what can truly be verified, never a faked pass or fail.
Measured in your browser with the real GZIP algorithm (CompressionStream), the same one web servers use.
Frequently asked questions
Why does compression matter?
GZIP shrinks text files (HTML, CSS, JS) by 60 to 80 percent before they travel over the network, so pages load faster. Browsers decompress automatically; visitors never notice except in speed.
Are these results real or estimated?
Paste mode is fully honest: your browser really compresses your sample with the same GZIP algorithm servers use, and the byte counts are measured, not estimated. The URL mode can only report what the network actually reveals, and says so plainly when it cannot verify.
How can I verify compression another way?
Most sites block cross-origin reads (CORS), and proxies often strip the original headers. A sure check from your own machine: open a terminal and run curl -sI -H "Accept-Encoding: gzip" yoursite.com, then look for content-encoding: gzip in the reply.
Preview
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