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GZIP and Brotli Checker

See whether a page is sent compressed, with which methods, and how much each one saves.

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About GZIP and Brotli Checker

Text compression is one of the cheapest speed wins, and this GZIP and Brotli checker shows whether it's really working. Maybe you just turned on gzip in Nginx or Apache, enabled Brotli at your CDN, or a speed report says text isn't compressed. Enter a URL and we request the page four ways: with no compression, with gzip, with Brotli and with Zstandard. The first CSS file and the first JavaScript file on the page get the same four requests.

The Compression table shows the uncompressed size, the transfer size for each method and the share saved, so you know exactly how much each method takes off. The checks confirm that the page is compressed, whether Brotli is enabled, whether your CSS and JavaScript are compressed too, and whether the server sends Vary: Accept-Encoding, which stops caches from handing compressed files to clients that can't read them. For the full picture of load time, run the Website Speed Test.

How to use GZIP and Brotli Checker

  1. 1
    Enter the URL

    Use a normal HTML page, such as your home page.

  2. 2
    Click Check

    We fetch the page, its first CSS and first JavaScript file with each method.

  3. 3
    Compare the sizes

    The Compression table shows each method's transfer size and the share saved.

  4. 4
    Fix what's flagged

    Turn on gzip or Brotli for the flagged file types and add Vary: Accept-Encoding.

Why use Cubfile for this

  • Four methods side by side

    No compression, gzip, Brotli and Zstandard, compared on the same file.

  • CSS and JavaScript too

    The first stylesheet and script on the page are tested alongside the HTML.

  • Real savings

    Transfer size and percentage saved for every method the server supports.

  • Vary header check

    Makes sure caches know the response depends on Accept-Encoding.

FAQ

GZIP and Brotli Checker: questions and answers

How do I turn on gzip compression?
In Nginx, set gzip on and list the text types in gzip_types, and in Apache, enable mod_deflate. Most CDNs and hosting panels have a compression switch, and once it's on, run the checker again. If you're not sure which server software the site runs, the Website Technology Detector can tell you.
Is Brotli better than gzip?
Brotli usually makes text about 15 to 20% smaller than gzip, and every modern browser supports it. Keep gzip on as well for older clients.
What is Zstandard?
A newer compression method that recent versions of Chrome, Edge and Firefox accept. Few servers offer it yet, so an empty Zstandard column is normal.
The page is compressed, so why is my CSS flagged?
Compression is usually set per file type. The checker tests your first CSS and JavaScript file separately, so add text/css and application/javascript to the types your server compresses. The HTTP Header Checker shows the Content-Type each file is actually sent with.
Is the GZIP and Brotli checker free?
Yes. It needs no sign-up, doesn't use daily tasks, and the result isn't stored.
Share GZIP and Brotli Checker with a friendIt runs in any browser, and they can try it without signing up.

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