I am looking for a extension that allows the user to block IndexedDB reads/writes from user-defined sites.

IndexedDB is a form of locally stored data that websites can create on your computer. Unfortunately, Firefox has no built-in option to delete this data. Clearing the browser's cache will never delete this data. This creates serious issues, and possibly some ones as well.

Any cost is acceptable for the add-on. Any operating system is acceptable. Open source or closed source is acceptable, but a preference (not requirement) for open source.

Must be compatible with Firefox 42 or later.

  • Thanks a lot! So is this the same as "LocalStorage" (which can e.g. be explored using the Foundstone HTML5 Local Storage Explorer addon) – and you're just using a different term for it? In that case, Self-Destructing Cookies might come in handy.
    – Izzy
    Commented Dec 6, 2015 at 22:58
  • @Izzy No. That's for HTML5 Local Storage, which is yet another form of local storage that websites can create on your computer. This article, csimms.botonomy.com/2011/05/… , although outdated, has a good overview of just a few of the different technologies. Commented Dec 6, 2015 at 23:07
  • @Izzy If you aren't familiar with how the data is stored on the system, you can see IndexedDB storage by using the Storage Inspector, which is included as part of the Firefox Developer Tools (available in the default Firefox installation). It only shows the IndexedDB storage for the current site, however. Commented Dec 6, 2015 at 23:09
  • Yuck, very local stuff, getting me confused. "DOM Storage", "LocalStorage" (see these addons) – and now another one. Nevermind, take a look at Permissions Auto Registerer, seems to be your candidate. If not, here're the alternatives. None tried by me, hence no answer but a comment ;) If it fits, let me know and I make it a full-fledged answer.
    – Izzy
    Commented Dec 6, 2015 at 23:11
  • 1
    @Izzy It is simple to completely disable IndexedDB (which is what PrivaConf does), but some sites use IndexedDB for useful functionality. What I need is something that will block it on a per-site basis. Commented Dec 6, 2015 at 23:20

1 Answer 1


Use the Page Info menu next to the location bar which shows the URL:

disable offline storage in firefox

Maintain Offline Storage is a site permission. It used to be in the preferences UI, but was dropped in FF46. You now get to it per site via urlbar info icon > Right Arrow > More Information > Permissions

This is meant to control indexedDB as far as I know (and it has said that in the user.js since the start over 2 years ago).

and enable the Storage Inspector from the Developer Tools settings to test:

Storage Inspector

and check the console to verify:

IndexedDB Disabled in Firefox


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