Anonymizer Nevercookie is a Firefox add-on designed to ensure protection against the Evercookie API. The plugin extends Firefox’s private browsing mode by preventing Evercookies from identifying and tracking users.

Evercookie is a new, more persistent cookie form that enables the storage of cookie data in a number of different locations, such as Flash cookies and various locations of HTML5 storage. This allows websites to track user behavior even when users have enabled private browsing. Because an Evercookie stores data in locations outside of where standard cookies are stored, an Evercookie can rebuild itself unless users go through a number of steps to completely clear and reset their local storage.

Anonymizer Nevercookie simplifies this process and eliminates the manual steps required to completely remove Evercookies. And it does so without also removing all of the necessary cookies that a user actually wants to keep, such as those for browsing history and remembered logins. When Anonymizer Nevercookie is engaged along with Firefox’s private browsing mode, it quarantines an Evercookie and removes it after the browsing session.