Performance Tools

GZIP Compression Checker

Check whether a website compresses its pages before sending them.

Not sure what to enter? Try an example: wikipedia.org

Free & instant No signup How to use FAQ

Enter a URL to see whether the server compresses the page and which encoding it uses.

What is GZIP compression?

GZIP compresses text responses - HTML, CSS, JavaScript, JSON - before the server sends them, typically making them 60-80% smaller so pages load faster. The browser decompresses them automatically. This checker reports whether a site returns compressed content (GZIP or Brotli).

How to check whether GZIP is enabled

Enter the domain in the box above.
Click Check Compression.
Look for gzip or br in the Content-Encoding result.
If there is none, enable compression in your web server (for example gzip on; in Nginx) or at your CDN.

Related checks

To check the newer Brotli format, use the Brotli Compression Checker.
For all compression settings together, see the Compression Summary.

If Gzip is off, it is usually one setting in your host's control panel, a line in .htaccess, or a toggle on your CDN. JustChecker tracks response times so you can see the difference once compression is switched on.

Frequently Asked Questions

Text files such as HTML, CSS and JavaScript usually shrink by 60-80%, so pages download several times faster on slow connections.

Most hosts enable it by default; on Apache use mod_deflate (the .htaccess Generator has an option), on Nginx set gzip on. CDNs compress automatically.

No. JPG, PNG and WebP are already compressed, so GZIP adds work without saving space. Shrink images with the Image Compressor instead.

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