Mozilla Firefox is renowned for its flexibility and powerful customization options. Advanced users often take advantage of the about:config interface to tweak and optimize their browser experience. The about:config page offers access to dozens of hidden preferences and settings that can alter Firefox’s behavior, appearance, and performance.
Below is a curated list of useful and frequently modified about:config commands and settings that can help tech-savvy users get the most out of their browsing.
Accessing the about:config Interface
To access Firefox’s advanced settings:
- Open Firefox.
- Type about:config in the address bar and hit Enter.
- Click “Accept the Risk and Continue” when the warning page appears.
Now you’ll see a powerful search-based interface to modify or create preferences.
Most Popular about:config Commands & Settings
Privacy and Security
- privacy.resistFingerprinting – Set to true to hinder fingerprinting techniques employed by trackers.
- network.cookie.cookieBehavior – Controls third-party cookies:
- 0 = Accept all cookies
- 1 = Block third-party cookies
- 2 = Block all cookies
- 5 = Dynamic first-party isolation
- browser.safebrowsing.phishing.enabled – Toggle to false to disable Google Safe Browsing phishing protection.
Performance Optimization
- browser.cache.disk.enable – Set to false to disable disk cache for better privacy and sometimes performance.
- gfx.webrender.all – Set to true to force enable WebRender GPU acceleration.
- network.http.pipelining – Set to true to enable pipelining, which may improve page load performance.
User Interface Tweaks
- browser.tabs.closeButtons – Controls tab close button visibility:
- 0 = No close buttons
- 1 = Show close button on active tab only
- 2 = Don’t show close buttons
- 3 = Show close button on each tab (default)
- browser.urlbar.trimURLs – Set to false to show full URLs (including “http://”) in the address bar.
Download and File Handling
- browser.download.useDownloadDir – When set to false, Firefox asks where to save each file.
- browser.helperApps.neverAsk.saveToDisk – Useful for administrators to bypass ‘Save As’ dialog for specific MIME types.
Advanced Tweaks for Power Users
- dom.webnotifications.enabled – Set to false to completely disable web push notifications.
- layout.css.devPixelsPerPx – Modify screen DPI scaling; useful for high-resolution monitors. Default is -1.0.
- media.hardware-video-decoding.enabled – Enable or disable hardware acceleration for video playback.
Creating New Preferences
If you cannot find a preferred setting, Firefox allows users to create one manually:
- Click the + icon beside the search bar.
- Choose the type: Boolean, Number, or String.
- Enter a name and value, then click the check mark to save.
Important Notes
- Always back up your profile before making extensive changes.
- Some changes may impact browser stability or security.
- Use caution and research unfamiliar settings before modifying them.
FAQ – Frequently Asked Questions
- Is it safe to modify about:config settings?
- Yes, when done carefully. However, incorrect changes may cause Firefox to behave unpredictably or crash.
- Can I reset settings back to default?
- Yes. Use the reset icon next to each modified preference or delete your prefs.js file in the Firefox profile folder.
- Do about:config changes sync across devices?
- No, these preferences are stored locally per profile and do not sync with Firefox Accounts.
- Where is the Firefox profile folder located?
- Go to about:support > click “Open Folder” next to Profile Folder.
- Will Firefox updates override about:config changes?
- In rare cases, major updates may reset or deprecate certain preferences. It’s recommended to review about:config settings after major version updates.
Using about:config, Firefox users can tailor virtually every aspect of their browsing environment. Whether for performance, privacy, or usability enhancements, this gateway to advanced features empowers users to take full control of their browser.
