Tweak Firefox with about:config

Jack Wallen
Mar 6, 2009
Updated • Dec 28, 2012

If you use Firefox you probably have had to enter the address about:plugins to see if the plugin you just installed actually did install. But did you know there is another "about" address you can use to do some serious tweaking in the famous open source web browser? That address: about:config.

The about:config address is a special location that allows you to change configuration options in Firefox. Most of these options aren't every-day, end-user-friendly options. Instead these options can look a little overwhelming to the pedestrian. But to those that hold no fear of tweaking, about:config is your friend. In this article I will show you a few tweaks in about:config so you can get familiar with how this special configuration address is used.

When you first load about:config in your Firefox browser you will have to click an "I'll Be Careful, I Promise" button that warns you what you are about to do can void your warranty. It's okay, really, go ahead and push the button.

Once you push the button you will see entries like this:

accessibility.accesskeycausesactivation     default     boolean     true

The first entry is the Preference Name. Next is the Status, followed by the Type, and the Value. Each entry follows this same format.To change a value in an entry you only have to right click that entry and, depending up on the type of value, click the Toggle entry in the popup menu. If the value is, say, an integer a Modify entry will appear allowing you to modify the value of the entry.

Within the about:config there are various categories:

  • Accessability
  • Advanced
  • Alerts
  • Browser
  • Config

Your about:config will show each entry arranged according to category. You will also find a very large amount of entries - don't let that overwhelm you. You can also search your entries (thanks to the handy Filter.

So let's take a look at a few about:config entries that will make a noticeable change in the speed of Firefox. These entries are:

  • network.http.pipelining.
  • network.http.proxy.pipelining
  • network.http.pipelining.maxrequests

The fastest way to find this is to enter pipelining in the Filter.

Once you have found them you will do the following:

  • Set network.http.pipelining to "true" by right clicking the entry and selecting Toggle.
  • Set network.http.proxy.pipelining to "true" by right clicking the entry and selecting Toggle.
  • Set network.http.pipelining.maxrequests to value like 50 by right clicking the entry, selecting Modify, entering the new value, and clicking OK.

Now let's add a totally new entry to help speed up Firefox. Click anywhere and select New and then select integer. A small window will open asking for the name of the new entry. Enter nglayout.initialpaint.delay and give it a value of "0" (no quotes) when prompted.

Firefox should now be noticeably faster.

Of course using about:config isn't limited to speed. Browse through the listing of entries and you will notice that nearly every possible configuration option imaginable is there. Play around with familiar entries and see how far you can tweak Firefox. Just use caution, if you don't know what an entry does make sure you look it up before you edit it. A good place to find information on each entry is the official Firefox about:config Entries database.


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  1. irene said on May 4, 2009 at 7:08 am

    thanks a lot for the tips..
    now i can smile with my firefox
    thanks a lot guys

  2. RG said on March 6, 2009 at 9:44 pm

    Some thing that speeds up the client side must surely have an effect server side. Wouldn’t pipelining and maxrequests – used widely – affect server performance? I remember there were discussions earlier in Firefox’s history about those kinds of settings and I decided not to change them on my PC.

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