July 3, 2025 / 3 min read

Updated: August 29, 2025

This checklist will walk you (and me) through the settings and extensions I use to improve my privacy when using Firefox.

If you’re looking for a web browser that offers a high degree of privacy out of the box with minimal setup, Brave is a common choice. However, I prefer Firefox for several reasons:

• Firefox is developed by the nonprofit organization Mozilla.
• I value Mozilla’s commitment to open source software.
• Firefox is not based on Chromium. Brave, like most browsers, is based on Chromium, which is developed primarily by Google. While there are many web browsers to choose from, I’ve decided Firefox is best for me. This post is a checklist of how I’ve configured it to better protect my privacy while browsing the web.

1. Basic Privacy Settings

Access Firefox’s settings by clicking the menu button (three horizontal lines) in the top-right corner and selecting “Settings.”

• Change Default Search Engine: In the Search tab, change the “Default Search Engine” to a privacy-respecting option like DuckDuckGo.
• Enable HTTPS-Only Mode: In the Privacy & Security tab, scroll down to “HTTPS-Only Mode” and select “Enable HTTPS-Only Mode in all windows.”
• Disable Telemetry: Still in Privacy & Security, scroll to “Firefox Data Collection and Use” and uncheck all the boxes to stop Firefox from sending data back to Mozilla.
• Set Enhanced Tracking Protection to Strict: Under Privacy & Security, set “Enhanced Tracking Protection” to Strict. This offers stronger protection against trackers. If a site breaks, you can easily disable it for that specific site by clicking the shield icon in the address bar.

2. Recommended Extensions

• Install uBlock Origin: A comprehensive content blocker that stops ads and tracking scripts, which speeds up page loading and enhances privacy.
• Install ClearURLs: This extension automatically removes tracking elements from URLs, helping prevent another form of web tracking.
• Install Privacy Badger: From the Electronic Frontier Foundation, this extension automatically learns to block invisible trackers. Instead of relying on blocklists, it discovers trackers based on behavior.

3. Advanced Configuration (about:config)

To access this, type about:config into the address bar and accept the warning.

Warning: Changing advanced configuration preferences can impact Firefox performance or security. Proceed with caution.

• Isolate Cookies to the First-Party Domain:
• Search for privacy.firstparty.isolate and set its value to true.
• This prevents cookies from tracking you from one site to another, but it can break single sign-on on some websites.
• Resist Fingerprinting:
• I previously set privacy.resistFingerprinting to true to make my browser fingerprint less unique.
• It caused minor display issues on some sites and broke image uploads to Bluesky, so I set it back to false. By following this checklist, you can significantly improve your privacy while using Firefox. Please let me know if I’m missing anything in the comments.