Browser extensions

Decentraleyes addon loads CDN resources locally

Decentraleyes by Thomas Rientjes recently got an update and is now available in version 2.0.2, the biggest change is that is now compatible with Chrome and Opera, besides this it also was tested with Pale Moon and the ESR Firefox version. Basically you install the addon and then check against a test page if it’s working or not.

How does the addon work?

The addon  emulates centralized content delivery (CDNs) which means it prevents  connection requests from reaching networks like Google, Facebook & Co.

Basic explanation. Picture Firefox AMO page

An advance explanation can be found here among a FAQ here. The addon doesn’t collect any information accoirding to their source code and Privacy Policy.

The addon comes with the following supported CDN’s:

Google Hosted Libraries, Microsoft Ajax CDN, CDNJS (Cloudflare), jQuery CDN (MaxCDN), jsDelivr (MaxCDN), Yandex CDN, Baidu CDN, Sina Public Resources and UpYun Libraries among several others, the list gets updated ….

The following resources are integrated:

AngularJS, Backbone.js, Dojo, Ember.js, Ext Core, jQuery, Modernizr, MooTools, Prototype, Scriptaculous, SWFObject, Underscore.js and a Web Font Loader.

Oh come on yet another addon – do I really need it?

Yes, it compliments your adblocker and I see this addon as useful because most adblockers doesn’t block delivery of CDN by default which means you not need to work with any external strict blocking policy, just install it and that’s it.

Option menu is for advance users. You can add exclusions in case you get troubles with a domain.

What’s wrong with CDN’s?

Usually nothing but ask yourself why you need a connection to them when you can load them locally?! The benefit is obvious, less bandwidth and you are secured against possible attacks however, the downside is that it might break a page some functions. Personally I haven’t found any of my daily pages which got a problem while using the addon, that’s also the reason why the exclusion section on my screenshot is empty.

Does it work together with uBlock/uMatrix/NoScript?

It does work together with such ads-/script-blockers. It’s mentioned in the FAQ, that the default modes are compatible, if you use stronger options/modes you might need some adjustments but this is well explained.

Testing the addon


You can visit the test page, to check if the addon works or not. The addon doest’t need any configuration by default, you install it and that’s it, takes 30 seconds. The integrated counter display how many CDN’s are injected.



This addon is a must and it solves a lot of problems, locally loaded resources are always faster than remotely loaded resources even if a powerful fast network makes them available on the Internet and since connections are not made anymore to these networks, there is no privacy impact as well.

The addon isn’t perfect but it’s a good start, what is missing is an integrated indicator to show or highlight what was locally injected and maybe a warning when something could’t be loaded in case e.g. while xyz CDN isn’t supported.

It definitely get my recommendation because the developer did overall a good job and the mentioned things are something which is fixable in future versions.

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