Updated 8 March 2019


Mozilla Firefox provides many integrated tools for a detailed configuration.
To get to the hidden settings of Firefox, go to the following:


Default settings

parameter value description
browser.fixup.alternate.suffix .ru Domain name extension
browser.startup.homepage Firefox start page
browser.startup.homepage_override.mstone ignore Skip first launch setup
browser.tabs.warnOnClose false Do not warn when closing more that one tab Droid Sans Mono Slashed Droid Sans Times New Roman


parameter value description
browser.cache.disk.capacity 102400 Disk cache, requires disabling "browser.cache.disk.smart_size.enabled"
browser.cache.disk.smart_size.enabled false Disables cache size auto-tuning
browser.cache.use_new_backend 1

Enable the new HTTP caching system. Improves the responsiveness of the interface
|browser.sessionhistory.max_total_viewers|3|Maximum number of cached pages in each tab|
|browser.sessionstore.interval|60000|Autosave interval in milliseconds|
|browser.tabs.animate|false|Tab animation. Disabling this accelerates tab moving, page opening, etc.|
|browser.tabs.remote.autostart|true|Multiprocessor mode|
|browser.tabs.remote.autostart|true|Processing each tab in a separate process|
|dom.ipc.plugins.asyncInit.enabled|true|Asynchronous plugin initialization|
|dom.ipc.processCount|4|Number of processors used (support enabled in browser.tabs.remote.autostart)|
|javascript.options.asyncstack|true|Asynchronous stacking|
|memory.free_dirty_pages|true|Releasing unused pages after closing tabs|
|memory.free_dirty_pages|true|Releases memory after closing tabs|
|network.http.pipelining.max-optimistic-requests|8|Maximum number of requests|
|network.http.pipelining.ssl|true|Pipeline requests via SSL connection|
|network.http.pipelining|true|Use multiple queries in one connection to the server|
|network.http.proxy.pipelining|true|Use multiple queries in one connection to the server when using a proxy|
|network.dnsCacheEntries|200|Number of cached DNS names|
|network.dnsCacheExpiration|240|Time in seconds after which the DNS name cache expires|
|network.http.request.max-start-delay|5|Time in seconds before establishing a new connection to the server, to pause queries before creating a new connection|
|browser.sessionstore.max_tabs_undo|5|Number of Firefox tabs that you can reopen if they close|
|browser.sessionstore.max_windows_undo|2|Number of recently closed windows, similar to browser.sessionstore.max_tabs_undo|
|browser.bookmarks.max_backups|2|Number of backups for Firefox to close faster|
|browser.newtabpage.enhanced|false|Do not suggest sites in new page tabs. "datareporting.sessions.current.clean" must be enabled|
|datareporting.sessions.current.clean|true|Do not collect information about the pages viewed. Option required to disable "browser.newtabpage.enhanced"|
|extensions.e10sBlockedByAddons|false|Allow to block multiprocessing by extensions|
|extensions.e10sBlocksEnabling|false|Allow to block multiprocessing|

Do not collect Firefox usage statistics. Reduce memory consumption, stop sending data to Mozilla, for privacy and performance reasons

parameter value
browser.selfsupport.url [HTML_REMOVED]
browser.tabs.crashReporting.sendReport false
datareporting.healthreport.about.reportUrl [HTML_REMOVED]
datareporting.healthreport.infoURL [HTML_REMOVED]
datareporting.healthreport.uploadEnabled false
dom.ipc.plugins.flash.subprocess.crashreporter.enabled false
dom.ipc.plugins.reportCrashURL false
experiments.enabled false
experiments.manifest.uri [HTML_REMOVED]
experiments.supported [HTML_REMOVED]
extensions.getAddons.cache.enabled false
network.allow-experiments false
security.ssl.errorReporting.enabled false
toolkit.crashreporter.infoURL [HTML_REMOVED]
toolkit.telemetry.archive.enabled false
toolkit.telemetry.cachedClientID [HTML_REMOVED]
toolkit.telemetry.infoURL [HTML_REMOVED]
toolkit.telemetry.server [HTML_REMOVED]

Disable integrated social services

parameter value
social.directories [HTML_REMOVED]
social.remote-install.enabled false
social.share.activationPanelEnabled false
social.shareDirectory [HTML_REMOVED]
social.toast-notifications.enabled false
social.whitelist [HTML_REMOVED]

Disable the "Pocket" service and delete your ID, thus making your browser anonymous

parameter value
extensions.pocket.api [HTML_REMOVED]
extensions.pocket.enabled false
extensions.pocket.oAuthConsumerKey [HTML_REMOVED] [HTML_REMOVED]

Consider the SSL connection as untrusted if the query for a repeated "session renegotiation" is incorrect

parameter value
security.ssl.treat_unsafe_negotiation_as_broken true

Disable sharing and geolocation

parameter value [HTML_REMOVED]
geo.enabled false
geo.wifi.uri [HTML_REMOVED]

Force proxy off (by default, system settings will be used)

parameter value
network.proxy.type 0

Prevent scripts from manipulating Firefox windows

parameter value
dom.disable_beforeunload true
dom.disable_window_move_resize true
dom.disable_window_open_feature.close true
dom.disable_window_open_feature.menubar true
dom.disable_window_open_feature.minimizable true
dom.disable_window_open_feature.personalbar true
dom.disable_window_open_feature.titlebar true
dom.disable_window_open_feature.toolbar true

Forbid sending tracking "pings" when clicking on links and closing pages

parameter value
beacon.enabled false

Disable the Adobe Primetime Content Decryption Module (DRM) plugin, which allows to track your browser

parameter value
browser.eme.ui.enabled false
media.eme.apiVisible false

Disable access from sites to cameras and microphones. Disable other multimedia features that are not used on regular sites, but are a threat to privacy or security

parameter value
camera.control.face_detection.enabled false
media.getusermedia.screensharing.allowed_domains [HTML_REMOVED]
media.getusermedia.screensharing.enabled false
media.navigator.enabled false
media.video_stats.enabled false

Enable statistics

parameter value description false Do not send search queries. If you have disabled this function, you will still get hints when trying to search something, but only based on the local search history.
dom.battery.enabled false Disable the Battery API monitor
dom.enable_performance false Do not send information about the start and end time of the page load.
extensions.getAddons.cache.enabled false Send information about the installed add-ons on a daily basis
network.http.pipelining.aggressive true Hold problematic connections to the server
network.proxy.socks_remote_dns true Disable DNS bypassing proxy settings


parameter value description
browser.reader.detectedFirstArticle true Disable the "Read View" notification
privacy.trackingprotection.introCount 20 Disable the "Hw does the tracking protection work" notification
general.warnOnAboutConfig false Warning when trying to go to about:config


parameter value description
browser.urlbar.trimURLs false Display the "http: //" prefix in the address bar
privacy.trackingprotection.enabled true Block suspicious sites that are not trusted in the Internet, as they are thought to be engaged in surveillance of users. Unfortunately, if you turn this off, you will not be allowed to see built-in Yandex maps with itineraries.
privacy.donottrackheader.enabled true Warn the sites that you do not want to be tracked
dom.popup_maximum 5 Maximum number of pop-up windows opened by a script
browser.rights.3.shown true
Do not inform about the permissions
startup.homepage_welcome_url [HTML_REMOVED] Welcome line at the first start
browser.slowStartup.notificationDisabled true Disables calculation of browser startup time with warning if it starts slowly
offline-apps.allow_by_default false Do not use Offline App Cache without explicit permission from the user