Privacy Badger
The EFF's tracker blocker that learns what follows you and blocks only the trackers, not the ads.
About
Privacy Badger is the Electronic Frontier Foundation's free, open-source browser extension for Chrome, Firefox, Edge, Brave, Opera, and Firefox for Android, released in 2014 under the GPLv3. Unlike list-based blockers it learns: when it sees a third-party domain tracking you across three or more sites, it starts blocking it, which catches trackers that never made it into a filter list. It also sends Global Privacy Control and Do Not Track signals, replaces embedded trackers like video players and comment widgets with click-to-activate placeholders, and strips outgoing link click-tracking on Facebook and Google.
The EFF's framing is deliberate. Privacy Badger is not an ad blocker; it targets the tracking, and ads that cannot function without their trackers die as a side effect, while non-intrusive ads load fine. That makes it the rare privacy tool built by a digital-rights nonprofit with no acceptable-ads business model, which was the EFF's stated reason for building it rather than endorsing Disconnect, Adblock Plus, or Ghostery. The limitations are real: it can break pages and features, it has no mobile app beyond Firefox for Android, and because it learns locally it starts naive and improves over days of browsing. Version numbering now runs on year-based releases, latest 2026.8.7 as of August 2026.
What it can do
- Automatic learning tracker detection across sites
- Global Privacy Control and Do Not Track signaling
- Click-to-activate placeholders for embedded widgets
- Outgoing link click-tracking removal
- Per-domain blocking sliders: green, yellow, red
- Site-level disable for pages it breaks
- Breakage reporting to the EFF
- Open-source GPLv3 development on GitHub
Setup
Install free from the Chrome Web Store, Firefox Add-ons, or other extension stores; no account and no configuration needed.
Prerequisites
A supported desktop browser or Firefox for Android; nothing to sign up for.
Use cases
Works with
Trust score — 7/10
Scored 7/10 (verified tier, metrics-v1). Evidence: Wikipedia and EFF sources confirm the May 2014 launch, GPLv3 license, learning-based three-strike tracker blocking, GPC/DNT signaling, click-to-activate placeholders, and the 2026.8.7 stable release; TechRadar notes the no-mobile-app limitation. Strengths: nonprofit-built with no ad-industry business model and catches trackers blocklists miss. Docked for: (1) weaker than dedicated ad blockers and breaks some sites; (2) no mobile app outside Firefox for Android; (3) learning means slow ramp-up and less coverage than maintained lists. License: GPL-3.0.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 7.0/10
- Maintenance · recency, releases, issue load
- 7.0/10
- Openness · license + docs
- 10.0/10
- Manual review · sanity read + red-flag check
- 7.0/10
- · EFF release 1 May 2014; Chrome, Firefox, Edge, Brave, Opera, Firefox for Android
- · Learning-based blocking: trackers seen across 3+ sites get blocked automatically
- · Sends Global Privacy Control and Do Not Track signals
- · Click-to-activate placeholders for embedded widgets; removes link click-tracking
- · Not an ad blocker by design; only targets tracking
- · No mobile app outside Firefox for Android; can break some pages
- · Year-based releases; 2026.8.7 stable (August 2026)
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.