I am creating a "hand made" HTTP 1.0, 1.1 server. I recently integrated zip lib so now I can stream encoded gziped data in and out. I wonder which major browsers (alive ones - IE6-IE10, Chrome, FF, etc.) send Accept-Encoding: deflate, gzip, ... and so can handle Content-Encoding: gzip today? Which of them send any quality expectations? Which of them can send encoded gziped post request and multypart/form data to my server?

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    Shouldn't you be relying on the Accept-Encoding header anyway? Or are you just asking out of curiosity?
    – Flimzy
    Aug 22, 2015 at 17:15
  • @Flimzy If you're storing files that have been encoded in advance (which you might do to reduce CPU load, to decrease disk space usage, to increase the level of compression, or because you're serving files from an entirely static server), then you don't really have the luxury to adhere to the Accept-Encoding header. If you can obey the header, of course you should, but given the virtually-universal support of gzip nowadays, it's okay to build your website to require gzip support. Mar 28, 2017 at 3:03
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    @haydenschiff of course you can still honor the accept header. If you're storing gzipped data, you are already prepared to unzip it to serve it if the accept header dictates.
    – Flimzy
    Mar 29, 2017 at 0:35

1 Answer 1


Basically every browser nowadays supports deflate/gzip. This page lists many browsers and version numbers. Here's a summary plus some newer browsers:

  • Netscape 6+ (Netscape 4-5 does, but with some bugs).
  • Internet Explorer 5.5+ (July 2000) and IE 4 if set to HTTP/1.1.
  • Opera 5+ (June 2000)
  • Lynx 2.6+ (some time before 1999)
  • Firefox 0.9.5+ (October 2001)
  • Chrome since forever
  • Safari since forever (as far as I can tell)

As you can see: for almost 15 years, there's full support, and nobody uses a more than 15 year old browser.

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    +1 I was kind of confused, as this seems like a non-existent problem. @user1049847 maybe you need to expand your question above?
    – Su'
    Nov 19, 2011 at 10:02
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    And to add to this, no browser will send a gzip compressed request but almost all accept a gzip compressed response. See "Why can't browser send gzip request?" on StackOverflow. Nov 19, 2011 at 10:18
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    @Su' is right - any browser that supports gzip will send the Accept-Encoding header so you don't need to care exactly which browsers support this. Send gzip when they tell you they're able to receive it. Nov 19, 2011 at 13:51
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    The question is relevant. If you are serving static files from Amazon S3, MS Azure and others (as many do) you won't be able to dynamically respond to the accept-encoding header. Also compressing on the fly puts an added load on the CPU.
    – QFDev
    Sep 27, 2013 at 18:56
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    @QFDev if you are serving static files, you can create one version that is gzipped and one that is not and check for accept-encoding/gzip and change the static files served accordingly. Oct 27, 2015 at 17:18

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