Web Storage Viewer for Firefox privacy add-on

Web Storage Viewer is a brand new browser add-on for the Firefox web browser that displays data stored by websites on the local system.

While many Internet users are aware of cookies and the danger to privacy they represent by now, the majority is probably unaware of other tracking means.

Web Storage, also known as DOM storage, HTML5 storage, session storage or local storage is such an option.

Part of the issue comes from missing options in browsers to manage and delete Web Storage easily. While you may manage Web Storage on a site by site basis using Firefox's Development Tools, there is no option available currently to manage all items stored at once.

Firefox users may delete all Web Storage, or more precisely Local Storage, by clearing everything under Clear Recent History in the History menu (tap on the Alt-key to display it or use Ctrl-Shift-Del).

Web Storage Viewer

The free add-on Web Storage Viewer changes that. It adds a new button to the privacy page of the Firefox options that, when activated, opens the list of sites that used Web Storage to store data on the local system.

Do the following to display the list of permanently stored data bits by sites in Firefox:

1. Install the Web Storage Viewer extension. You find the link in the summary box below this review.
2. Load about:preferences#privacy afterwards to display Firefox's privacy preferences.
3. Locate the new Show Web Storage button there, and click on it.

All web storage items are displayed in an overlay on the screen afterwards.  The list is sorted by site, with each site grouped in its own folder for easier access.

A click opens the list of items that the site stored on the local computer. Some sites may use local storage to save user account information, game saves, configuration preferences and other relevant data that is beneficial to the user. Others may use local storage however for tracking purposes.

A tap on the Delete-key on the keyboard removes the selected item from Firefox. You may remove individual items, e.g. a particular entry stored by a site, or all bits of data that a site stored on the local system.

You may furthermore click on remove all at the button to clear all Web Storage items in one go. The method won't touch other history related information like the browsing history.

The Web Storage Viewer interface ships with a search at the top. This can be particularly useful if you want to jump to specific entries quickly, or list all matching entries regardless of site that stored them.

You may use it to search for a username or an email address for instance.

The add-on does not list Session Storage items in the interface. The reason for this is that session storage items are specific to tabs, and removed automatically when the session closes. You may use Firefox's Storage Inspector for that, but since the data is not carried over to future sessions, it cannot  be used for tracking purposes.

Closing Words

Show Web Storage is an excellent add-on for Firefox. It can be used to manage web storage entries, or clear all locally stored items that a site placed or all of them easily.

Firefox users who value their privacy should definitely check it out provided that they don't use other means already to manage Web Storage in the web browser.