Make YouTube faster on Firefox with this extension

Martin Brinkmann
Mar 26, 2020
Firefox, Firefox add-ons

Google launched a new design of the company's YouTube website recently that made the site slow on Firefox when compared to Google Chrome. Firefox users who open YouTube in the browser may notice extended loading times and other issues after the design change was published by Google.

We covered a discussion about YouTube being purposefully slower on non-Chrome browsers by Mozilla Technical Program Manager Chris Peterson on Twitter back in mid 2018. Peterson stated that Google used a deprecated API only implemented in Chrome on YouTube that made the site slower on non-Chrome browsers.

The Firefox extension Disable Polymer on YouTube fixes the issues caused by the new design on Firefox by disabling it. All the extension does is append the parameter disable_polymer=true to the YouTube URL.

speed up youtube in firefox

Firefox users may give it a try without installing the extension to compare the performance on classic YouTube and the new YouTube design. Chance is that classic YouTube loads faster and performs better than the current design of the site.

All the extension does is automate the process by adding the parameter to the YouTube URL automatically.

The polymer redesign of YouTube has made the site very slow for Firefox users. This add-on adds the "disable_polymer" option to YouTube URLs in order to revert back to the old classic design.

Just install the extension in Firefox and it will add the parameter to YouTube's URL automatically. The extension requires access to data on YouTube but that is the only special permission that it requests during installation; good.

Note that the functionality depends on Google keeping the parameter enabled on YouTube. The return to classic YouTube to speed it up on Firefox won't work anymore should Google decide to remove it from the site.

The parameter may also be useful to non-Firefox users who prefer the classic design over YouTube's new layout.

Another alternative that users have is to use a third-party tool to watch YouTube videos, e.g. video players such as SMPlayer support YouTube playback.

Now You: How often do you use YouTube?

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Author Rating
3.5 based on 19 votes
Software Name
Disable Polymer on YouTube
Software Category
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  1. Elad Karako said on June 11, 2020 at 9:13 am

    if you are missing the dark theme, you can try this pure css extension.
    It works without rule set on most websites.

    and yt being slow is an old thing so that’s why I’ve created (for myself at first) – Boostaler.

    all in the release section as well.

  2. Elad Karako said on June 11, 2020 at 9:05 am

    oh, I’ve got this polymer thing covered for ages…
    the trick is to also pre modify the links on the page, otherwise for every click you will reload the page twice (which is dumb), also the URL argument tend to “disappear” after the browser updates a variable in memory and uses push history api to “refresh” the page without polymer. which is fine.

    the web extension updates yt cookie and halts the ajax page loading engine (spf) favoring classic page load to be compatible with the no polymer design.

  3. ace said on March 30, 2020 at 6:52 am

    My eyes! No dark mode option on this version of youtube smh

  4. Sophie said on March 28, 2020 at 9:04 am

    I have a different problem, that I hoped this Addon might address, but it doesn’t. Since the last couple of weeks, every video in Firefox I try to reach, returns the error….

    An error occurred. Please try again later. (Playback ID: uOm4lBY90DoOINFS)
    Learn More

    That “ID” changes all the time.

    If I fully whitelist YT on Ublock Origin, the error goes away, but the adverts then start.

    Yet interestingly, my copy of Vivaldi, which also has Ublock Origin is not affected, so I’ve been having to forget Firefox and turn to Vivaldi for any YT video.

  5. Peter Newton said on March 27, 2020 at 6:47 pm

    Thank you for that.

    Peter Newton [London UK]

  6. Tukirito said on March 27, 2020 at 6:38 pm

    Here is another solution, check the first comment on this reddit link, instead of having to install an extension you can just edit a cookie on the youtube page, it will be safer and better than installing an extension.

  7. scylla said on March 27, 2020 at 12:56 am

    I upload a lot of videos and am finding the new uploader very cumbersome, so I’d welcome some way of retaining Classic – therefore I just tried IE11 – yes, it offers Classic, but YouTube has a bright yellow notice up “We’ll stop supporting this browser soon. For the best experience, please update your browser.”

  8. Topical said on March 26, 2020 at 11:55 pm

    I don’t understand. This is old news. Why this is being posted now. YouTube changed it’s layout in 2018/2017 and this was discussed before. An Edge employee complained, Firefox employee showed YouTube was using deprecated polymer and last year if I remember correctly Google even said they don’t use that anymore and performance should be the same now in all browsers. YouTube loads just fine in my Firefox 74, Windows 10.

    1. cwiho said on June 5, 2020 at 3:43 pm

      polymer is slower for me (average computer). Either google is crap or mozilla is crap.
      Polymer is also ugly as hell, everything is magnified.
      I think they just dont care tbh.

  9. Peter Newton said on March 26, 2020 at 11:00 pm

    Hi all,

    Just one question :)

    How secure is this plugin/addon ? Can anyone be certain its not sending stats, data, or telemetry? Perhaps some internet monitoring i/o might be in order before you install it?

    Just thought I’d point that out.

    Peter Newton [London Uk]

    1. Gill Bates said on March 27, 2020 at 2:04 pm

      addons are open source. you can download them and look at their source code.

      heres the codes for this addon :
      (as you can see theres no external url to send your data)

      var targetUrl = “*”;
      var disable_option = “disable_polymer=true”;

      function rewriteUrl(req) {
      if (!req.url.includes(“disable_polymer”))
      if (req.url.includes(“?”))
      return { redirectUrl: req.url + “&” + disable_option};
      return { redirectUrl: req.url + “?” + disable_option};

      { urls: [targetUrl], types: [“main_frame”]},

  10. Stv said on March 26, 2020 at 10:58 pm

    The only add-on you need is uBlock Origin. Try again with it!
    What would happen if we should install add-ons for every poorly built website?! Ridiculous.

    The less add-on you have the faster your browser be.

    1. cwiho said on June 5, 2020 at 3:38 pm

      You can’t disable youtube polymer with uBlock origin, can you?
      If so, please tell me how. Thanks

  11. Weilan said on March 26, 2020 at 10:45 pm

    Before I bought my new computer, YouTube with the Photon layout was slow even when I used Chrome on my old computer. But now that I have the processing power, it works well on every browser.

    I think it’s just that the layout is resource-heavy and older computers struggle with it regardless of the browser.

    That’s one thing I don’t like about many “modern/modernized” websites, software and games – they are so badly optimized that they rely on high computer specs to work smoothly. For example all the UWP Apps on Windows 10 load very slowly on another computer in my house that has only an HDD, but on my computer that has SSD, it loads instantaneously.

    It’s a shame that most developers are so sloppy, I don’t think it’s just Google’s fault in this case.

  12. Gabriele said on March 26, 2020 at 10:04 pm

    i’m using a script. it has a very simple code and works ok

  13. rickst29 said on March 26, 2020 at 7:24 pm

    Using Firefox 74 on Linux, versus Chrome 80: This version of Firefox defaults to preferences for AV1 as “enabled, use Dav1d” and preferences for VP9 as “enabled” but NOT “preferred”. I SWAG that these preferences cause YouTube to use AV1 (and Opus audio), with the dav1d video decoder.

    CPU Utilization, playing an HD video, is SMALLER than Google Chromium (~10% versus ~13%) and it also stutters less. (Stuttering was visible in Chromium with full-screen layout on a 4K screen, there were no such artifacts on Firefox.) Why? AV1 uses less bandwidth than VP9, vastly less than VP8 or H.264 – so the same caching size can hold more seconds (or portions of seconds) of video, than it can with less efficient protocols.

    Unless your profile is messed up, or your firefox didn’t include the DAV1D Decoder, or your firefox is old – allowing firefox and youtube to use AV1, *without* degrading into a lesser video codec, seems to be WAY better. Even better than Chrome!

    This may be a recent Firefox development, and it might not be available in ‘Windows’ or ‘OSX’. Maybe someone else can experiment on those platforms.

  14. empirefall said on March 26, 2020 at 5:37 pm

    I am currently use the web extension ‘Fast YouTube Load’ which I am assuming does the same thing

  15. 12bytes said on March 26, 2020 at 4:44 pm

    for those already using a redirect add-on, you don’t need to install another add-on to disable Polymer – search “Firefox Tweaks and Fixes and Styles and Things”

  16. JG said on March 26, 2020 at 3:54 pm

    Big improvement on Firfox on my slow machine.

    I was previously using ‘You Tube Classic’ extension; alongside several others (Adblocker for YT, Enhancer for YT, Distraction Free YT, Privacy Enhanced mode for YT).


  17. Daniel said on March 26, 2020 at 2:05 pm

    Or use FreeTube?

    1. Klaas Vaak said on March 27, 2020 at 10:49 am

      @Daniel: thanks for sharing.

  18. Yuliya said on March 26, 2020 at 1:48 pm

    It’s a Trabant (Firefox); no matter how much you fiddle with it, it won’t perform like a BMW (Chromium).

    1. Dude without a suit said on March 28, 2020 at 9:10 am

      Ah yes, ignore something about Google purposefully shitting on other browser, eh?

      Yuliya is a Chrome cultist as always.

      1. Yuliya said on March 28, 2020 at 9:04 pm

        google has nothing to do with the fact that firefox is slow and outdated: [chromium81vsfirefox73.png]

  19. Gill Bates said on March 26, 2020 at 12:56 pm

    Peterson stated that Google used a deprecated API only implemented in Chrome on YouTube that made the site slower on non-Chrome browsers.

    is this about polymer v1.0 (a.k.a. shadowdom v0)? afaik youtube stopped using that already. newer polymer versions are supported in firefox. plus i dont notice any slowdowns. looks like outdated news.

    1. mholo said on March 26, 2020 at 5:59 pm

      You are right. That whole story was blown way out of proportion.

      It wasn’t that Google was intentionally slowing down other browsers, it’s just that it implemented v0 of that spec and no other vendor implemented that, so in order for it to work in other browsers it was “patched” (polyfilled) using JavaScript and that can never be as fast as a native implementation directly in the browser.

      I think they are using Polymer V2 on YouTube now which uses v1 of that spec and doesn’t have the same issue because browser support is way better (,

  20. Tom Hawack said on March 26, 2020 at 12:25 pm

    Disabling YouTube’s Polymer is an old work-around, several Firefox extensions as well as user scripts propose it. I’ve tried no-polymer but the layout was awful because I use several CSSs which don’t render YouTube pages correctly.

    Here with Firefox (74 x64) YouTube appears quickly, maybe less than with Chrome but certainly not slowly; maybe because of several uBlock Origin YouTube dedicated filters, maybe because I block cookies for YouTube, maybe because I refuse sites to access to IndexedDB (Elad Karako’s API-Killer-IndexedDB extension for Firefox). No idea but the result is a relative velocity.

    But should I run YouTube on an out-of-the-box Firefox that such an extension or script aimed at rendering YouTube free of its Polymer would likely be welcomed. YouTube is a very — call it complicated, complex, sophisticated — piece of code, I admire techies who garb and shake it for users’ better comfort and privacy.

    1. Jan said on March 29, 2020 at 12:14 pm

      Hi Tom
      I try to find the “Elad Karako’s API-Killer-IndexedDB extension for Firefox” but I can not find it in the FF add-on . Maybe it is my incompetence!!
      Can you tell me how to get it?

      1. Tom Hawack said on March 30, 2020 at 10:32 am

        @Jan, hi

        ‘Elad Karako’s API-Killer-IndexedDB extension for Firefox’ :

        Description : []
        Download : []

        All Elad Karako extensions are signed and install flawlessly on Firefox, they just don’t happen to be available on AMO unfortunately.

    2. Karol said on March 28, 2020 at 1:23 pm

      Agree – Youtube is superfast for me on two Win10 boxes, both on my 2016 ‘old’ XPS and 2017 age Latitude 7000 series notebook.

      Albeit top of the range laptops on purchase – once Win10 / Firefox is correctly configured with adblocking extensions (with Open-WRT router / adblock as well) youtube flies here.

      Not really sure what the fuss is about – be it not for this article I would never realize youtube is supposed to be slow, or that it was slow, since redesign. I never noticed…

  21. Pierre said on March 26, 2020 at 12:24 pm

    Yes, it works

  22. JohnSno said on March 26, 2020 at 12:18 pm

    I think Google might not remove the old youtube design anytime soon. Because the polymer redesign has already been the default for two years now and they still keep the old design around. They probably know that polymer is a monstrosity that performs like crap even on Chrome. Maybe they’re tweaking polymer, but that complete shitfest might as well be thrown away and they decide to adopt ReactJS. So hopefully they will keep the old design around for a little longer until they get their…react together ;)

    1. mholo said on March 26, 2020 at 5:50 pm

      They are probably keeping it around for older browsers like Internet Explorer 10 or 11, because people still use those for some reason. If you open YouTube in IE11 you get the old design by default, no need for that ?disable_polymer=true stuff.

      And even if they decide to switch they won’t switch to React for sure, they would probably use Angular since that’s their project.

  23. Iron Heart said on March 26, 2020 at 11:12 am

    Google will disable the old layout eventually. Stop gap extension.

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