How to Opt-Out of Optimizely ( in One Click

What does “waiting for ‘’ mean?

In short, ‘cdn’ means Content Distribution Network and Optimizely is a service that provides A/B Testing for websites. Optimizely makes A/B testing possible by swapping images or changing the structure or style of a web page. To do this, it has to load additional instruction on to the web page being tested.

The reason you are seeing “waiting for” as you are trying to load a site is most likely because the network you are using is somewhat slow. It just happens to be Optimizely information (likely an image page content for the A/B test) that is coming across the network while you are waiting on a slow network connection.

How to Opt-Out of Optimizely in One Click

The quick solution is to create a bookmarklet to opt out of Optimizely for any page that you don’t want Optimizely to load on. To do this:

  • Create a new bookmark in your browser
  • Instead of adding in a URL add the following:
javascript:(function(){window.location += '?optimizely_opt_out=true'}())
  • click the bookmarklet when loading sites that are using Optimizely.

Done! You’ve successfully opted out of Optimizely. You should no longer have to wait on for that page. This should remain in effect until you clear that site’s cookies.

Optimizely is not Bad!

(In fact is pretty awesome)

The reason I wrote this is because a friend tweeted his frustration about waiting on “” The unfortunate part is that, while Optimizely appears to be the culprit of a slow-loading web page, it’s actually far more likely that a slow network connection is to blame.

You probably like Optmizely but you just didn’t know it. Or until now, you didn’t even know about it. Optimizely is used for A/B testing on tons of sites that you visit, from to A/B testing is done to improve sites and provide a better user experience for people like you. And 99.999% of the time you don’t notice it because it is making your life better. Only in this rare occasion is it bothering you. (And it’s because of your network)

How The Bookmarklet Works

The bookmarklet issues some instructions, coded into javascript, to the browser.

javascript:(function(){window.location += '?optimizely_opt_out=true'}())

This basically says the following:

“Here comes a javascript function”


“Take the current URL (aka window.location) and append to it the parameter to opt out of Optimizely.” This is explained further on

window.location += '?optimizely_opt_out=true'

“Do these instructions! When the URL is changed, the browser reloads the page with the opt out parameter. This tells Optimizely that no tests should be run on the page and should not load any additional images or information on to the page.” (And you won’t have to wait for it)


I hope this works out for you. Just remember, you don’t hate Optimizely, you hate slow internet connections!


  1. russ

    funny how any issues of slowing down are NEVER EVER having to do with anything BUT my network
    its a wonder it works at all!

    1. Trevor Fox

      No kidding! “its a wonder it works at all!” – I say that at least once every day that I use the Internet 🙂

  2. John

    The reason web pages load slowly and show “waiting for” is “most likely because the network you are using is somewhat slow”. err, no. It is because optimizely is slowing down page loading. It is only VISIBLE because connections are slow. On at least one occasion, this little “bug” stopped me from shopping on a particular site entirely.

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