Open Firefox in Private Mode by Default

By  on  

Opening a Firefox Private Window is oftentimes the first step persons who value privacy do when they open their browser.  That made me think:  can you configure Firefox to open in private mode by default?  It turns out you can.


When you type about:config in the address bar of Firefox, you are brought to a screen listing hundreds of options you can update to customize your Firefox experience.  about:config rightly comes with a warning that by modifying these options you may cause problems with your install; luckily the setting we want to update is simply a boolean.



Update the browser.privatebrowsing.autostart setting, which defaults to false, to true.  Updating this setting ensures that Firefox windows and tabs open in private mode.  You will need to close and reopen your browser for the updated setting to kick in.

Recent Features

Incredible Demos

  • By
    Create Keyboard Shortcuts with Mousetrap

    Some of the finest parts of web apps are hidden in the little things.  These "small details" can often add up to big, big gains.  One of those small gains can be found in keyboard shortcuts.  Awesome web apps like Gmail and GitHub use loads of...

  • By
    dat.gui:  Exceptional JavaScript Interface Controller

    We all love trusted JavaScript frameworks like MooTools, jQuery, and Dojo, but there's a big push toward using focused micro-frameworks for smaller purposes. Of course, there are positives and negatives to using them.  Positives include smaller JS footprint (especially good for mobile) and less cruft, negatives...


  1. Also is available in Preferences -> Privacy -> Never remember history

  2. Hallo, David,

    same question like Fakultet:

    Can I translate this article into German and link back to it? Which license applies?

    Kind regards,


  3. Won’t this store cookies on the private firefox mode since it now opens standardly? Or will it be a separate firefox mode everytime I open firefox?

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!